### Home > PC3 > Chapter 4 > Lesson 4.1.1 > Problem4-19

4-19.

Solve the system:  \begin{aligned}[t] x^2+y^2=25 \\ xy=12 \end{aligned}

Rewrite the second equation as:

$y=\frac{12}{x}$

Substitute the expression for $y$ from Step 1 into the top equation.