Question

Suppose y varies directly with x.When x is 7,y is 21 Write the equation that relates x and y

Answer 1

Answer:

`y=3x`

Step-by-step explanation:

Given that y varies directly with x, we have:

`\begin{gathered} y\propto x \\ \Rightarrow y=kx \end{gathered}`

Where k is constant.

When x = 7, y = 21. From here, we can obtain the value of k

21 = 7k

k = 21/7 = 3

Since k = 3, the equation that relates x and y is:

`y=3x`