CG SCERT (Chhattisgarh Board) Class 9 Mathematics Solutions | 2026-27 Official Edition
Complete 100% textbook-grounded CG Board Class 9 Mathematics Chapter 4 Solutions: Polynomials (बहुपद) in Bilingual Format (English & Hindi Medium).
Official Textbook Exercises
End-of-Chapter Exercises (Solutions)
अभ्यास के सभी प्रश्नों के हल
Question 1
(i) 4×2 – 3x + 5 Solution / : It is a polynomial because the…
अभ्यास प्रश्न
📝 Question:
- (i) 4x2 – 3x + 5
- Solution / : It is a polynomial because the exponent of variable x in all terms is a whole number (2, 1, 0). / x
- (ii) z + 3/z
- Solution / : It is not a polynomial because z + 3/z = z + 3z-1, where the power of z is -1, which is not a whole number. / z + 3z-1 z -1
- (iii) √y + 2y + 3 (or y1/2 + 2y + 3)
- Solution / : It is not a polynomial because √y = y1/2, where the exponent is 1/2, which is not a whole number. / y 1/2
- (iv) x2 + 2/3x + 2
- Solution / : It is a polynomial because the powers of variable x are whole numbers. / x
- (v) x10 + y3 + t50
- (i) 3x3 + 2x2 + 3x + 2 (Textbook variation 3x2 + 2x2 + 3x + 2)
- Solution / : Combining 3x2 + 2x2 = 5x2, the coefficient of x2 is 5 (or 2 if 3x3 term). / x2 5
- (ii) 3x2 + 1
- Solution / : Coefficient of x2 is 3. / x2 3
- (iii) 2 – 5x2 + 1/2x3
- Solution / : Coefficient of x2 is -5. / x2 -5
- (iv) 1/2x2 + 2
- Solution / : Coefficient of x2 is 1/2. / x2 1/2
- (v) x4 + x3 + 1/4x2
- Solution / : Coefficient of x2 is 1/4. / x2 1/4
- (i) x2 + 1/5x + 5
- Solution / : Coefficient of x = 1/5, Constant term = 5. / x = 1/5, = 5
- (ii) x2 + 7
- Solution / : Coefficient of x = 0, Constant term = 7. / x = 0, = 7
- (iii) x2 + 2x
- Solution / : Coefficient of x = 2, Constant term = 0. / x = 2, = 0
- (i) Binomial of degree 4 / 4 :
- Solution: x4 + 3 or 3x4 + 4
- (ii) Trinomial of degree 6 / 6 :
- Solution: y6 + 3y + 3 or t6 + 3t – 5
- (iii) Monomial of degree 5 / 5 :
- Solution: 3x5 or z5
- (i) x3 – 6x2 + x + 1 → Degree = 3
- (ii) y9 – 3y7 + 3/2y2 + 4 → Degree = 9
- (iii) 3 – y3z → Sum of powers = 3 + 1 = 4. Degree = 4
- (iv) x2y – 2x + 1 → Sum of powers = 2 + 1 = 3. Degree = 3
- (v) 5t – 11 → Degree = 1
- (vi) 7 → Constant polynomial 7 = 7x0. Degree = 0
- Expressions: (i) x3 + x2 + x + 1, (ii) 9x3, (iii) y + y2 + 3/4, (iv) t + 3, (v) y – y3, (vi) 8, (vii) 2x2 + 3, (viii) P2 – P + 5, (ix) x + 2/3, (x) 4, (xi) -u/4 + 3/2, (xii) -3/7.
- Categorization / :
- Constant Polynomials: (vi) 8, (x) 4, (xii) -3/7
- Linear Polynomials: (iv) t + 3, (ix) x + 2/3, (xi) -u/4 + 3/2
- Binomials: (v) y – y3, (vii) 2x2 + 3
- Trinomials: (iii) y + y2 + 3/4, (viii) P2 – P + 5
- (i) x = 0
- Solution / : p(0) = 5(0)3 – 2(0)2 + 3(0) – 2 = -2
- (ii) x = 1
- Solution / : p(1) = 5(1)3 – 2(1)2 + 3(1) – 2 = 5 – 2 + 3 – 2 = 4
- (iii) x = -2
- Solution / : p(-2) = 5(-2)3 – 2(-2)2 + 3(-2) – 2 = 5(-8) – 2(4) – 6 – 2 = -40 – 8 – 6 – 2 = -56
- (i) p(x) = 4x3 + 2x2 – 3x + 2
- p(0) = 4(0) + 2(0) – 3(0) + 2 = 2
- p(-1) = 4(-1)3 + 2(-1)2 – 3(-1) + 2 = -4 + 2 + 3 + 2 = 3
- p(2) = 4(2)3 + 2(2)2 – 3(2) + 2 = 32 + 8 – 6 + 2 = 36
- p(3) = 4(3)3 + 2(3)2 – 3(3) + 2 = 108 + 18 – 9 + 2 = 119
- (ii) p(r) = (r – 1)(r + 1)
- p(0) = (0 – 1)(0 + 1) = -1
- p(-1) = (-1 – 1)(-1 + 1) = 0
- p(2) = (2 – 1)(2 + 1) = 1 × 3 = 3
- p(3) = (3 – 1)(3 + 1) = 2 × 4 = 8
- (iii) p(t) = 2/3t2 – 1/3t + 1/3
- p(0) = 0 – 0 + 1/3 = 1/3
- p(-1) = 2/3(-1)2 – 1/3(-1) + 1/3 = 2/3 + 1/3 + 1/3 = 4/3
- p(2) = 2/3(4) – 1/3(2) + 1/3 = 8/3 – 2/3 + 1/3 = 7/3
- p(3) = 2/3(9) – 1/3(3) + 1/3 = 6 – 1 + 1/3 = 5 + 1/3 = 16/3
- (iv) p(y) = (y2 – y + 1)(y + 1)
- p(0) = (1)(1) = 1
- p(-1) = (1 + 1 + 1)(-1 + 1) = 3 × 0 = 0
- p(2) = (4 – 2 + 1)(2 + 1) = 3 × 3 = 9
- p(3) = (9 – 3 + 1)(3 + 1) = 7 × 4 = 28
- (v) p(x) = x + 2
- p(0) = 0 + 2 = 2
- p(-1) = -1 + 2 = 1
- p(2) = 2 + 2 = 4
- p(3) = 3 + 2 = 5
- (i) p(x) = 3x + 1; x = -1/3
- p(-1/3) = 3(-1/3) + 1 = -1 + 1 = 0 ⇒ *Yes
- (ii) p(x) = x + 2; x = -2
- p(-2) = -2 + 2 = 0 ⇒ *Yes
- (iii) p(x) = 5x – 4; x = 5/4
- p(5/4) = 5(5/4) – 4 = 25/4 – 4 = 9/4 ≠ 0 ⇒ *No
- (iv) p(y) = y2 – 1; y = 1, -1
- p(1) = 12 – 1 = 0; p(-1) = (-1)2 – 1 = 0 ⇒ *Yes
- (v) p(t) = (t + 1)(t – 2); t = +1, -2
- p(1) = (2)(-1) = -2 ≠ 0 ⇒ *No
- (vi) p(x) = lx + m; x = -m/l
- p(-m/l) = l(-m/l) + m = -m + m = 0 ⇒ *Yes
- (vii) p(r) = 3r2 – 1; r = -1/√3, 1/√3
- p( ± 1/√3) = 3(1/3) – 1 = 1 – 1 = 0 ⇒ *Yes
- (i) p(x) = x + 6 ⇒ x + 6 = 0 ⇒ x = -6
- (ii) p(x) = x – 6 ⇒ x – 6 = 0 ⇒ x = 6
- (iii) p(y) = 5y ⇒ 5y = 0 ⇒ y = 0
- (iv) p(t) = at, a ≠ 0 ⇒ at = 0 ⇒ t = 0
- (v) p(r) = cr + d, c ≠ 0 ⇒ cr + d = 0 ⇒ r = -d/c
- (vi) p(u) = 3u – 6 ⇒ 3u = 6 ⇒ u = 2
- (vii) r(s) = 2s + 3 ⇒ 2s = -3 ⇒ s = -3/2
- (viii) p(x) = 5 – x ⇒ 5 – x = 0 ⇒ x = 5
- (ix) q(t) = 1/2t – 2/3 ⇒ 1/2t = 2/3 ⇒ t = 4/3
- (i) 2x2 + x + 1 and 3x2 + 4x + 5
- (2x2 + 3x2) + (x + 4x) + (1 + 5) = 5x2 + 5x + 6
- (ii) 8p2 – 3p + 4 and 3p3 – 4p + 7
- 3p3 + 8p2 + (-3p – 4p) + (4 + 7) = 3p3 + 8p2 – 7p + 11
- (iii) -5x3 + 9x2 – 5x + 7 and -2x2 + 7x3 – 3x – 8
- (-5x3 + 7x3) + (9x2 – 2x2) + (-5x – 3x) + (7 – 8) = 2x3 + 7x2 – 8x – 1
- (i) 3y2 + 2y – 5; 2y2 + 5 + 8y and -y2 – y
- Sum = (3 + 2 – 1)y2 + (2 + 8 – 1)y + (-5 + 5) = 4y2 + 9y
- Degree: 2
- (ii) 5 + 7r – 3r2; r2 + 7 and r2 – 3r + 5
- Sum = (-3 + 1 + 1)r2 + (7 – 3)r + (5 + 7 + 5) = -r2 + 4r + 17
- Degree: 2
- (iii) 4x + 7 – 3x2 + 5x3; 7x2 – 2x + 1 and -2x3 – 2x
- Sum = (5 – 2)x3 + (-3 + 7)x2 + (4 – 2 – 2)x + (7 + 1) = 3x3 + 4x2 + 8
- Degree: 3
- (i) t2 – 5t + 2 from 7t3 – 3t2 + 2
- (7t3 – 3t2 + 2) – (t2 – 5t + 2) = 7t3 + (-3 – 1)t2 + 5t + (2 – 2) = 7t3 – 4t2 + 5t
- (ii) 3p – 5p2 + 7 + 3p3 from 2p2 – 5 + 11p – p3
- (-p3 + 2p2 + 11p – 5) – (3p3 – 5p2 + 3p + 7) = (-1 – 3)p3 + (2 + 5)p2 + (11 – 3)p + (-5 – 7)
- = -4p3 + 7p2 + 8p – 12
- (iii) 5z3 + 7z2 + 2z – 4 from -3z2 + 11z + 12z3 + 13
- (12z3 – 3z2 + 11z + 13) – (5z3 + 7z2 + 2z – 4) = (12 – 5)z3 + (-3 – 7)z2 + (11 – 2)z + (13 + 4)
- = 7z3 – 10z2 + 9z + 17
- (i) (3x + 4) by (7x2 + 2x + 1)
- 3x(7x2 + 2x + 1) + 4(7x2 + 2x + 1) = 21x3 + 6x2 + 3x + 28x2 + 8x + 4
- = 21x3 + 34x2 + 11x + 4
- (ii) (5x3 + 2x) by (3x2 – 9x + 6)
- 5x3(3x2 – 9x + 6) + 2x(3x2 – 9x + 6) = 15x5 – 45x4 + 30x3 + 6x3 – 18x2 + 12x
- = 15x5 – 45x4 + 36x3 – 18x2 + 12x
- (iii) (p4 – 5p2 + 3) by (p3 + 1)
- p3(p4 – 5p2 + 3) + 1(p4 – 5p2 + 3) = p7 – 5p5 + 3p3 + p4 – 5p2 + 3
- = p7 – 5p5 + p4 + 3p3 – 5p2 + 3
- Example 1 / 1: Find zero of p(x) = 2x + 1.
- Solution / : Put 2x + 1 = 0 ⇒ 2x = -1 ⇒ x = -1/2.
- Example 2 / 2: Check if 0 or 2 are zeroes of x2 – 2x.
- Solution / : p(0) = 02 – 2(0) = 0; p(2) = 22 – 2(2) = 0. Both 0 and 2 are zeroes.
- Example 3 / 3: Add 3x3 – x2 + 5x – 4 and 3x2 – 7x + 8.
- Solution / : 3x3 + (-1 + 3)x2 + (5 – 7)x + (-4 + 8) = 3x3 + 2x2 – 2x + 4.
- Example 4 / 4: Add 3/2y3 + y2 + y + 1 and y4 – 1/2y3 – 3y + 1.
- Solution / : y4 + (3/2 – 1/2)y3 + y2 + (1 – 3)y + (1 + 1) = y4 + y3 + y2 – 2y + 2.
- Example 5 / 5: Subtract 4x2 + 3x – 2 from 9x2 – 3x – 7.
- Solution / : (9x2 – 3x – 7) – (4x2 + 3x – 2) = 5x2 – 6x – 5.
- Example 6 / 6: Subtract s(z) = 3z – 5z2 + 7 + 3z3 from x(z) = -z3 + 2z2 + 11z – 5.
- Solution / : (-z3 + 2z2 + 11z – 5) – (3z3 – 5z2 + 3z + 7) = -4z3 + 7z2 + 8z – 12.
- Example 7 / 7: Add 3x + 4 – 5x2, 5 + 9x, and 4x – 17 – 5x2. Find degree.
- Solution / : Sum = -10x2 + 16x – 8. Degree = 2.
- Example 8 / 8: Subtract r(x) = 2x2 – 3x – 1 from sum of p(x) = 3x2 – 8x + 11 and q(x) = -4x2 + 15. Find degree.
- Solution / : p(x) + q(x) = -x2 – 8x + 26. Difference = (-x2 – 8x + 26) – (2x2 – 3x – 1) = -3x2 – 5x + 27. Degree = 2.
- Example 9 / 9: Find sum and difference of p(x) = 4x3 + 3x2 + 2x – 1 and q(x) = 4x3 + 2x2 – 2x + 5.
- Solution / :
- Sum: 8x3 + 5x2 + 4
- Difference: x2 + 4x – 6
- Example 10 / 10: What should be added to 2u2 – 4u + 3 to get 4u3 – 5u2 + 1?
- Solution / : (4u3 – 5u2 + 1) – (2u2 – 4u + 3) = 4u3 – 7u2 + 4u – 2.
- Example 11 / 11: What should be subtracted from 2y3 – 3y2 + 4 to get y3 – 1?
- Solution / : (2y3 – 3y2 + 4) – (y3 – 1) = y3 – 3y2 + 5.
- Example 12 / 12: Multiply 2x2 + 3x + 4 by 3.
- Solution / : 3(2x2 + 3x + 4) = 6x2 + 9x + 12.
- Example 13 / 13: Multiply (2x + 5) × (4x + 3).
- Solution / : 2x(4x + 3) + 5(4x + 3) = 8x2 + 6x + 20x + 15 = 8x2 + 26x + 15.
- Example 14 / 14: Multiply (2x + 5) × (3x2 + 4x + 6), find degree.
- Solution / : Product = 6x3 + 23x2 + 32x + 30. Degree = 3.
- Example 15 / 15: Find p(x) · q(x) for p(x) = 2x + 3 and q(x) = x2 + x – 2.
- Solution / : (2x + 3)(x2 + x – 2) = 2x3 + 5x2 – x – 6.
💡 Solution:
- हल / हल: It is a polynomial because the exponent of variable x in all terms is a whole number (2, 1, 0). / यह एक बहुपद है क्योंकि चर x की घातें पूर्ण संख्याएँ हैं।
- हल / हल: It is not a polynomial because z + 3/z = z + 3z-1, where the power of z is -1, which is not a whole number. / यह बहुपद नहीं है क्योंकि z + 3z-1 में चर z की घात -1 है जो पूर्ण संख्या नहीं है।
- हल / हल: It is not a polynomial because √y = y1/2, where the exponent is 1/2, which is not a whole number. / यह बहुपद नहीं है क्योंकि चर y की घात 1/2 है जो पूर्ण संख्या नहीं है।
- हल / हल: It is a polynomial because the powers of variable x are whole numbers. / यह एक बहुपद है क्योंकि चर x की घातें पूर्ण संख्याएँ हैं।
- Solution / हल: It is a polynomial because the powers of variables x, y, t are whole numbers (10, 3, 50). / यह एक बहुपद है क्योंकि चरों की घातें पूर्ण संख्याएँ हैं।
- हल / हल: Combining 3x2 + 2x2 = 5x2, the का गुणांक x2 is 5 (or 2 if 3x3 term). / x2 का गुणांक 5 है।
- हल / हल: का गुणांक x2 is 3. / x2 का गुणांक 3 है।
- हल / हल: का गुणांक x2 is -5. / x2 का गुणांक -5 है।
- हल / हल: का गुणांक x2 is 1/2. / x2 का गुणांक 1/2 है।
- हल / हल: का गुणांक x2 is 1/4. / x2 का गुणांक 1/4 है।
- हल / हल: का गुणांक x = 1/5, अचर पद = 5. / x का गुणांक = 1/5, अचर पद = 5।
- हल / हल: का गुणांक x = 0, अचर पद = 7. / x का गुणांक = 0, अचर पद = 7।
- हल / हल: का गुणांक x = 2, अचर पद = 0. / x का गुणांक = 2, अचर पद = 0।
- Solution / :
- Sum = (x4 + 3x3 + 2x + 6) + (x4 – 3x2 + 6x + 2) = 2x4 + 3x3 – 3x2 + 8x + 8
- Subtracting x3 – 3x + 4:
- (2x4 + 3x3 – 3x2 + 8x + 8) – (x3 – 3x + 4) = 2x4 + 2x3 – 3x2 + 11x + 4
- Solution / :
- p(u) + q(u) = (u7 – u7) – u5 + 2u2 + u + (1 – 2) = -u5 + 2u2 + u – 1
- Degree: 5
- Solution / :
- Required polynomial = (x2 – x + 4) – (x3 – 3x2 + 6) = -x3 + (1 + 3)x2 – x + (4 – 6)
- = -x3 + 4x2 – x – 2
- Solution / :
- Required polynomial = (u6 – u – 4) – (u7 – 3u6 + 4u2 + 2) = -u7 + (1 + 3)u6 – 4u2 – u + (-4 – 2)
- = -u7 + 4u6 – 4u2 – u – 6
- Solution / :
- Required polynomial = (y3 – 3y2 + y + 2) – (y3 + 2y + 1) = (1 – 1)y3 – 3y2 + (1 – 2)y + (2 – 1)
- = -3y2 – y + 1
- Solution / :
- Required polynomial = (t2 + t – 7) – (t3 + t2 + 3t + 4) = -t3 + (1 – 1)t2 + (1 – 3)t + (-7 – 4)
- = -t3 – 2t – 11
- Solution / :
- p(x) · q(x) = (x3 + 7x + 3)(2x3 – 3) = x3(2x3 – 3) + 7x(2x3 – 3) + 3(2x3 – 3)
- = 2x6 – 3x3 + 14x4 – 21x + 6x3 – 9
- = 2x6 + 14x4 + 3x3 – 21x – 9
- Solution / :
- Degree of p(u) = 2
- Degree of q(u) = 2
- Degree of r(u) = 1
- Degree of product p(u)q(u)r(u) = 2 + 2 + 1 = 5