WAEC Further Mathematics Past Questions & Answers - Page 91

451.

A straight line makes intercepts of -3 and 2 on the x- and y- axes respectively. Find the equation of the line.

A.

2x + 3y + 6 = 0

B.

3x - 2y - 6 = 0

C.

-3x + 2y - 6 = 0

D.

-2x + 3y - 6 =0

Correct answer is D

Equation of a straight line : y = mx + b

where m = the slope of the line

b = y- intercept

Given the two points (-3, 0) and (0, 2).

\(m = \frac{2 - 0}{0 - (-3)} = \frac{2}{3}\)

\(y = \frac{2}{3}x + 2 \implies 3y = 2x + 6\)

\(-2x + 3y - 6 = 0\)

452.

Find the constant term in the binomial expansion of \((2x - \frac{3}{x})^{8}\).

A.

90720

B.

1296

C.

1120

D.

672

Correct answer is A

\((x)^{n}(x^{-1})^{8 - n} = x^{0}\)

\(x^{n} . x^{-8 + n} = x^{0} \implies n - 8 + n = 0\)

\(2n - 8 = 0 \implies n = 4\)

Constant term = \(^{8}C_{4}(2^{4})(3^{4}) = 70 \times 16 \times 81\)

= \(90720\)

453.

Find the values of x at the point of intersection of the curve \(y = x^{2} + 2x - 3\) and the lines \(y + x = 1\).

A.

(1, -2)

B.

(0, 4)

C.

(2, -3)

D.

(1, -4)

Correct answer is D

Equate the equation of the curve and the line in order to find their point of intersection ie The values of y in both equations. 

\(y + x = 1 \implies y = 1 - x\)

\(x^{2} + 2x - 3 = 1 - x\)

\(x^{2} + 2x + x - 3 - 1 = 0 \implies x^{2} + 3x - 4 = 0\)

\((x - 1)(x + 4) = 0\)

\(x = (1, -4)\)

454.

If P(x - 3) + Q(x + 1) = 2x + 3, find the value of (P + Q).

A.

0

B.

1

C.

2

D.

3

Correct answer is C

No explanation has been provided for this answer.

455.

A fair die is tossed twice. Find the probability of obtaining a 3 and a 5.

A.

\(\frac{5}{12}\)

B.

\(\frac{2}{3}\)

C.

\(\frac{1}{18}\)

D.

\(\frac{1}{36}\)

Correct answer is D

P(c and e) = \(P(c) \times P(e)\)

P(3) = \(\frac{1}{6}\)

P(5) = \(\frac{1}{6}\)

P(3 and 5) = \frac{1}{6} \times \frac{1}{6} = \frac{1}{36}\)