Question

If y2-x=7, find the positive
value of y when x=9

Answer 1

To find the positive value of \( y \) when \( x = 9 \) in the equation \( y^2 - x = 7 \), we start by substituting \( x \) with 9.

The equation becomes:

\[
y^2 - 9 = 7
\]

Next, we can solve for \( y^2 \):

\[
y^2 = 7 + 9
\]
\[
y^2 = 16
\]

Now, we take the square root of both sides to find \( y \):

\[
y = \sqrt{16}
\]

This gives us:

\[
y = 4 \quad \text{or} \quad y = -4
\]

Since we are looking for the positive value of \( y \), we take:

\[
y = 4
\]

Thus, the positive value of \( y \) when \( x = 9 \) is

\[
\boxed{4}
\]