WAEC Past Questions and Answers - Page 4017

20,081.

Factorize the expression x(a - c) + y(c - a)

A.

(a - c)(y - x)

B.

(a - c)(x - y)

C.

(a + c)(x - y)

D.

(a + c)(x + y)

E.

(a - c)(x + y)

Correct answer is B

x(a - c) + y(c - a)

= x(a - c) - y(a - c)

= (x - y)(a - c)

20,082.

What is the smaller value of x for which x\(^2\) - 3x + 2= 0?

A.

1

B.

2

C.

3

D.

4

E.

5

Correct answer is A

x\(^2\) - 3x + 2 = 0

x\(^2\) - 2x - x + 2 = 0

x(x - 2) - 1(x - 2) = 0

(x - 2)(x - 1) = 0

x = 1 or 2. The smaller value of x = 1.

20,083.

Solve the inequality: \(\frac{1}{3}(2x - 1) < 5\)

A.

x < - 5

B.

X<-6

C.

X<7

D.

x <8

E.

x < 16

Correct answer is D

\(\frac{1}{3}(2x - 1) < 5\)

\(2x - 1 < 15\)

\(2x < 16\)

\(x < 8\)

20,084.

Which of the following could be the inequality illustrated in the sketch graph above?

A.

y≥2x+3

B.

y≤-3x+3

C.

y < 3x+2

D.

y≤x +3

E.

y≥3x+2.

Correct answer is B

Gradient of the line = \(\frac{3 - 0}{0 - 1}\)

= -3

y = -3x + b.

Using (1,0), we have

0 = -3(1) + b

0 = -3 + b

b = 3

y = -3x + 3

\(\therefore\) The graph illustrates y \(\leq\) -3x + 3.

20,085.

Find the value(s) of x for which the expression is undefined: \(\frac{6x - 1}{x^2 + 4x - 5}\)

A.

+4 or+1

B.

-5 or +1

C.

-5 or -1

D.

+5 or -1

E.

\(\frac{1}{6}\)

Correct answer is B

\(\frac{6x - 1}{x^2 + 4x - 5}\)

The expression is undefined when \(x^2 + 4x - 5 = 0\)

\(x^2 + 5x - x - 5 = 0\)

\(x(x + 5) - 1(x + 5) = 0\)

\((x - 1)(x + 5) = 0\)

The expression is undefined when x = 1 or -5.