Question

How do you solve the system `x² + y² = 16` and `x + y = 4`?

Answer 1

`y = 4 - x -> x^2 + (4 - x)^2 = 16`

`x^2 + 16 - 8x + x^2 = 16`

`2x^2 - 8x = 0`

`2x(x - 4) = 0`

`x = 0 and 4`

`0 + y = 4 or 4 + y = 4`

`y = 4 or 0`

The solution sets are `{0, 4} and {4, 0}`

Hopefully this helps!