Question

x^2+y^2=26
y-x=-6
Solving system of non linear equations

Answer 1

y=x+6
x^2+(x+6)^2
x^2+x^2+36=26
2x^2+36=6
2x^2=-10
x^2=5

Answer 2

^That's right. Just plug in X-6 for your Y and solve.