WAEC Past Questions and Answers - Page 3064

15,316.

Simplify \(\frac{4}{2x} - \frac{2x + x}{x}\)

A.

-1

B.

-2x

C.

2x

D.

\(\frac{2 - x}{2x}\)

Correct answer is A

\(\frac{4}{2x} - \frac{2 + x}{x} = \frac{4 - 2(2 + x)}{2x}\)

= \(\frac{4 - 4 - 2x}{2x} = \frac{-2x}{2x}\)

= 1

15,317.

Expand the expression(3a - xy)(3a + xy)

A.

9a2 - x2y2

B.

9a2 + x2y2

C.

9a2 - xy

D.

9a2 + x2y

Correct answer is A

(3a - xy)(3a + xy); (3a)2 - (xy)2

difference of two sqs; 9a2 - x2y2

15,318.

Find the smallest value of k such that 2\(^2\) x 3\(^3\) x 5 x k is a perfect square.

A.

3

B.

5

C.

15

D.

30

Correct answer is C

2\(^2\) x 3\(^3\) x 5\(^1\) x k;

2\(^2\) x 3\(^2\) x 3 x 5 x k

2\(^2\) x 3\(^2\) x 15 x k

smallest value for k

2\(^2\) x 3\(^2\) x 15 = 2\(^2\) x 3\(^2\) x 15\(^2\)

k = 15

15,319.

For what range of values of x is 4x - 3(2x - 1) > 1?

A.

x > -1

B.

x > 1

C.

x < 1

D.

x < -1

Correct answer is C

4x - 3(2x - 1) > 1

4x - 6x + 3 > 1

-2x > 1 - 3; 2x > -2

x < \(\frac{-2}{-2}\)

= x < 1

15,320.

make w the subject of the relation \(\frac{a + bc}{wd + f}\) = g

A.

\(\frac{a + bc - fg}{dg}\)

B.

\(\frac{a - bc + fg}{dg}\)

C.

\(\frac{a + bc - f}{dg}\)

D.

\(\frac{a + bc - dg}{dg}\)

Correct answer is A

\(\frac{a + bc}{wd + f}\) = g(cross multiply)

a = bc + wdg + fg

wdg = a + bc - fg

w = \(\frac{a + bc - fg}{dg}\)