Everything Maths Grade 11

7.2 CHAPTER 7. SOLVINGQUADRATIC EQUATIONS

(2b + 3)(b− 1) = 0

2 b + 3 = 0 or b− 1 = 0

b =

− 3

2

or b = 1

Step 5 : Check solutions in original equation

Both solutions are valid

Therefore, b =− 23 or b = 1

Exercise 7 - 1

Solve the following quadratic equations by factorisation. Some answers may be left in surd form.

1. 2 y^2 − 61 = 101


2. 2 y^2 − 10 = 0


3. y^2 − 4 = 10


4. 2 y^2 − 8 = 28


5. 7 y^2 = 28


6. y^2 + 28 = 100


7. 7 y^2 + 14y = 0


8. 12 y^2 + 24y + 12 = 0


9. 16 y^2 − 400 = 0


10. y^2 − 5 y + 6 = 0


11. y^2 + 5y− 36 = 0


12. y^2 + 2y = 8

13.−y^2 − 11 y− 24 = 0

14. 13 y− 42 = y^2


15. y^2 + 9y + 14 = 0


16. y^2 − 5 ky + 4k^2 = 0


17. y(2y + 1) = 15


18. y^5 −y 2 +y^3 + 2 =y 2 −−^62 y


19. yy−+1^2 =^2 yy−+1 7

More practice video solutions or help at http://www.everythingmaths.co.za

(1.) 0185 (2.) 0186 (3.) 0187 (4.) 0188 (5.) 0189 (6.) 018a

(7.) 018b (8.) 018c (9.) 018d (10.) 018e (11.) 018f (12.) 018g

(13.) 018h (14.) 018i (15.) 018j (16.) 018k (17.) 018m (18.) 018n

(19.) 018p