Question

If y varies directly with x, And y=35 when x=5, Find x when y=-7

Answer 1

Since \( y \) varies directly with \( x \), we can express this relationship with the equation:

\[
y = kx
\]

where \( k \) is the constant of proportionality.

Given that \( y = 35 \) when \( x = 5 \), we can find \( k \):

\[
35 = k(5)
\]

Solving for \( k \):

\[
k = \frac{35}{5} = 7
\]

Now that we have the value of \( k \), our equation becomes:

\[
y = 7x
\]

Next, we need to find \( x \) when \( y = -7 \):

\[
-7 = 7x
\]

Solving for \( x \):

\[
x = \frac{-7}{7} = -1
\]

Thus, the value of \( x \) when \( y = -7 \) is:

\[
\boxed{-1}
\]