Mathematics 1999 Waec Past Questions and Answers

Question 16 :

• WAEC 1999

If \(y = \sqrt{ax-b}\) express x in terms of y, a and b

A. \(x = \frac{y^2-b}{a}\)
B. \(x = \frac{y+b}{a}\)
C. \(x = \frac{y-b}{a}\)
D. \(x = \frac{y^2 + b}{a}\)

Question 17 :

• WAEC 1999

Given that \(81\times 2^{2n-2} = K, find \sqrt{K}\)

A. \(4.5\times 2^{n}\)
B. \(4.5\times 2^{2n}\)
C. \(9\times 2^{n-1}\)
D. \(9\times 2^{2n}\)

Question 18 :

• WAEC 1999

Simplify \(\frac{4}{x+1}-\frac{3}{x-1}\)

A. \(\frac{x+7}{x^2 - 1}\)
B. \(\frac{x-7}{x^2 + 1}\)
C. \(\frac{x-7}{x^2 - 1}\)
D. \(\frac{x-11}{x^2 - 1}\)

Question 19 :

• WAEC 1999

If y varies inversely as x\(^2\), how does x vary with y?

A. X varies inversely as y²
B. X varies inversely as y
C. X varies directly as y²
D. X varies directly as y

Question 20 :

• WAEC 1999

If \(tan x = \frac{1}{\sqrt{3}}\), find cos x - sin x such that \(0^o \leq x \leq 90^o\)

A. \(\frac{\sqrt{3}+1}{2}\)
B. \(\frac{2}{\sqrt{3}+1}\)
C. \(\frac{\sqrt{3}-1}{2}\)
D. \(\frac{2}{\sqrt{3}-1}\)