Chapter 4: Quadratic Equations

Exercixe - 6

Solve the following quadratic equation:

1. x2 - x - 20 = 0

3. 6x2 + 31x + 40 = 0

5. 16x2 - 24x = 0

7.

9. abx2 +(b2 - ac) x - bc = 0

2. 9x2 - 3x - 2 = 0

4. x2 + 6x + 5 = 0

6. 25x2 - 30x + 9 = 0

8.

10. x2 - 4qx + 4q2 = 0

Determine whether the following quadratic equations have real roots and if they have find them:

11.

13.

15.

17.

19.

12.

14. x2 + 3x + 1 = 0

16.

18.

20.

Find the value of k. If the following quadratic equation has equal roots:

21. k2x2 - 2(2k - 1) x + 4 = 0

22. x2 - 2kx + 7k - 12 = 0

23. ( k + 1) x2 - 2(k - 1) x + 1 = 0

24. If the equation (1 + m2) x2 + 2 mcx + (c2 - a2) = 0 has equal roots, prove that c2 = a2(1 + m2)

25. If the roots of the equation (a - b) x2 + (b - c) x + (c - a) = 0 are equal, prove that 2a = b + c.

Find the value of p for which the following equations has real roots:

26.2x2 + px + 8 = 0

27. 3x2 + 3x + p = 0

28. 5px2 - 8x + 2 = 0

Answers

1. -4, 5

4. -1, -5

7. -1

10. 2q

13. -9, 7

16.

19.

22. 3, 4

27.

2. -1/3, 2/3

5. 0, 3/2

8. -2

11. 5, 5/2

14.

17.

20.

23. 0, 3

28.

3. -1/2, 2/3

6. 3/5, 3/5

9. c/b, - b/a

12. 2, -5

15. No real roots.

 

18.

21. 1/4

26.

Subjects Maths (Part-1) by Mr. M. P. Keshari
Chapter 1 Linear Equations in Two Variables
Chapter 2 HCF and LCM
Chapter 3 Rational Expression
Chapter 4 Quadratic Equations
Chapter 5 Arithmetic Progressions
Chapter 6 Instalments
Chapter 7 Income Tax
Chapter 8 Similar Triangles