Question

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

Answer 1

`(x,y)=(0,4)` or `(4,0)`

Explanation:

From the second equation we get
`y=4-x`
pluggin this in the first equation

`x^2+(4-x)^2=16`
`x^2+16-8x+x^2=16`
`2x^2-8x=0`
`2x(x-4)=0`
so
`x=0`
or
`x=4`