Question

x- y = 5
x² + y² =13​

Answer 1

$x - y = 5 \\ x = 5 + y \\ x = 5y$

$x {}^{2} + y {}^{2} = 13 \\ x = \sqrt{ - y {}^{2} + 13 } \sqrt{ - y {}^{2} + 13 }$