Question

If y varies directly with x and y = -7 when x = -1, find x when y = -84.

Answer 1

since, y varies directly with x. therefore
\[y \alpha x \rightarrow y=kx...(k=constant)\]
Now at y = -7 when x = -1, k=?
\[-7=ktimes (-1).\rightarrow k= \frac{-7}{-1} =7\]
thus our eq of cvariation becomes
y= 7x
Now at y=-84, x=?

-84=7x
x=-84/7
x=-12

Answer 2

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