Question

Assume that y varies directly with x. If y=28 when x=7, find x when y=52

Answer 1

this indicates that y = 4x

Answer 2

"Assume that y varies directly with x" so we know that y = kx where k is some constant

Then we plug in x = 7, y = 28

y = kx

28 = k*7

28/7 = k

4 = k

k = 4

So the equation is y = 4x. Now plug in y = 52 and solve for x

Answer 3

\(\bf \begin{array}{llll}
\textit{something }&\textit{varies directly to }&\textit{something else}\\ \quad \\
\textit{something }&=(\textit{some value })&\textit{something else}\\ \quad \\
y&=(n)&x
\end{array}\)

Answer 4

y = 4(7)
28 = 28

52 = 4x
divide both sides by 4