Loading [MathJax]/jax/output/HTML-CSS/jax.js

WAEC Mathematics Past Questions & Answers - Page 311

1,551.

Solve: 6(x - 4) + 3(x + 7) = 3

A.

3/2

B.

2/3

C.

1/2

D.

1/3

Correct answer is B

6(x - 4) + 3(x + 7) = 3

6x - 24 + 3x + 21 = 3

9x - 3 = 3

9x = 6

x = 23

1,552.

Find the equation whose roots are -2/3 and -1/4

A.

12x2 + 11x + 2 = 0

B.

12x2 - 11x + 2 = 0

C.

x2 - 11/12x + 2 = 0

D.

12x2 - 11x - 2 = 0

E.

x2 - 11/12x - 2 = 0

Correct answer is A

x = 23 and 14

(x+23)=0;(x+14)=0

(x+23)(x+14)=0

x2+14x+23x+16=0

x2+1112x+16=0

12x2+11x+2=0

1,553.

Simplify: 1/4(2n - 2n+2)

A.

2n2 - 2n

B.

2n-2(1-2n)

C.

2n + 22n + 2

D.

22n

Correct answer is A

1/4(2n - 2n+2) = 2-2(2n - 2n x 22) = 2n x -2(1 - 22)= 22n-2
(20 - 22) = 22n-2 - 2n

1,554.

Simplify (3x+152y)÷6xy

A.

2y5x4

B.

9(2x5x)x2y2

C.

5x2y2

D.

c2y218y45x

E.

42y5x

Correct answer is A

(3x152y)÷6xy

= (6y15x2xy)÷6xy

= 6y15x2xy×xy6

= 3(2y5x)2xy×xy6

= 2y5x4

1,555.

Solve the equation: 3a + 10 = a2

A.

a = 5 or a = 2

B.

a = -5 or a = 2

C.

a = 10 or a = 0

D.

a = 5 or a = 0

E.

a = 5 or a = -2

Correct answer is E

3a + 10 = a2

a2 - 3a - 10 = 0

a2 - 5a + 2a - 10 = 0

a(a - 5) + 2(a - 5) = 0

(a - 5)(a + 2) = 0

a = 5 or a = -2.