To solve the system of equations below, Zach isolated [tex]$x^2$[/tex] in the first equation and then substituted it into the second equation. What was the resulting equation?
[tex]\[
\left\{
\begin{array}{l}
x^2 + y^2 = 25 \\
\frac{x^2}{16} - \frac{y^2}{9} = 1
\end{array}
\right.
\][/tex]
A. [tex]\(\frac{y^2 - 25}{16} - \frac{y^2}{9} = 1\)[/tex]
B. [tex]\(\frac{25 - y^2}{16} - \frac{y^2}{9} = 1\)[/tex]
C. [tex]\(\frac{x^2}{16} - \frac{25 - y^2}{9} = 1\)[/tex]
D. [tex]\(\frac{x^2}{16} - \frac{y^2 - 25}{9} = 1\)[/tex]