Question

Describe how to create the graph of the direct-variation relationship "y varies directly with x where y=-8.4 when x=4 ."

Answer 1

Plot the graph of y=2.1x.

Step-by-step explanation:

If y varies directly as x, we have the equation of variation as:

`\begin{gathered} y=kx \\ k\text{ is the constant of proportion} \end{gathered}`

When x=-4 and y=-8.4

`\begin{gathered} -8.4=-4k \\ k=-(8.4)/(-4) \\ k=2.1 \end{gathered}`

Substituting k back into the equation above, we have:

`y=2.1x`

So, to create the required graph, simply plot the graph of y=2.1x.