Question

Suppose y varies directly with x, and y = 8 when x = –6. What direct variation equation relates x and y? What is the value of y when x = –2?

Answer 1

The standard equation of direct variation is \(y = k x\) where \(k\) is a fixed constant.

Answer 2

So, you may write: \(8 = -6k\). That is the equation.

Answer 3

Find \(k\) by dividing both sides by \(-6\).

\( \color{Black}{\Rightarrow k = \Large {8 \over -6}}\)

\( \color{Black}{\Rightarrow k =\Large {4 \over -3}}\)

\( \color{Black}{\Rightarrow k = \Large {-4 \over 3}}\)

Answer 4

For the third question, you have \(k\) and \(x\). You have to find \(y\).

\( \color{Black}{\Rightarrow y = \Large{-4 \over 3} \normalsize \times -2}\)

Answer 5

Can you do the rest?
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