waecmaths question:
Calculate the gradient (slope) of the line joining points (–1, 1) and (2, –2)
Option A:
–1
Option B:
$-\tfrac{1}{2}$
Option C:
$\tfrac{1}{2}$
Option D:
1
waecmaths solution:
$\begin{align} & ({{x}_{1}},{{y}_{1}})=(-1,1) \\ & ({{x}_{2}},{{y}_{2}})=(2,-2) \\ & m=\frac{{{y}_{2}}-{{y}_{1}}}{{{x}_{2}}-{{x}_{1}}}=\frac{-2-1}{2-(-2)}=\frac{-3}{3}=-1 \\\end{align}$
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