1998 - WAEC Mathematics Past Questions and Answers - page 1

2x\(^2\) - 3x - 2 = 0

2x\(^2\) - 4x + x - 2 = 0

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

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

x = \(\frac{-1}{2}\) or x = 2

Take half the coefficient of m and square it
=> (-8/2)2 = k = 16

q = 10\(^{2.7078}\)

Antilog of 2.7078 = 510.2

In the 3rd quadrant, only the tan of angles are positive.

The 3rd quadrant = 180° < x < 270°

= \(\frac{0.63954}{0.003}\) 

moving the decimal places, we have

= \(\frac{639.54}{3}\)

= 213.18

\(\approxeq\) 210 (to 2 s.f.)

log\(_{10}\) a = 4

a = 10\(^4\)

= 10000

Let the actual length of the room = y m

\(\therefore \frac{y - 3.99}{y} \times 100% = 5%\)

\(100(y - 3.99) = 5y \implies 100y - 399 = 5y\)

\(100y - 5y = 399 \implies y = \frac{399}{95}\)

y = 4.2 m

From the diagram, \(\sin 30 = \frac{800}{x}\)

\(x = \frac{800}{\sin 30} \)

= \(\frac{800}{0.5} \)

= 1600 m