Question

How do you use the substitution method to solve x^2 + y^2=72 and x+y=0 finding the larger and smaller x value?

Answer 1

replace \(y\) by \(-x\) and solve

Answer 2

Can you explain that more?

Answer 3

x+y=0
x = -y
subst x = -y into the first equation (i.e. replace x with -y)