waecmaths question:
Which of the following number lines represents the solution to the inequality: $-9\le \tfrac{2}{3}x-7<5$
Option A:
Option B:
Option C:
Option D:
waecmaths solution:
$\begin{align} & -9\le \tfrac{2}{3}x-7<5 \\ & -9+7\le \tfrac{2}{3}x<5+7\text{ }\!\!\{\!\!\text{ Add 7 to both sides }\!\!\}\!\!\text{ } \\ & \text{-2}\le \tfrac{2}{3}x<12 \\ & -6\le 2x<36\text{ }\!\!\{\!\!\text{ multiply both sides by }3\} \\ & -3\le x<18 \\\end{align}$Option D
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