Question

Which two points satisfy y = -x2 + 2x + 4 and x + y = 4?

Answer 1

$y=-x^2+2x+4$ 
$x+y=4$
$y=4-x$
$4-x=-x^2+2x+4$
$x^2-3x=0$
$x(x-3)=0$
x=0 or x =3

for x = 0 y = 4
for x = 3 y = 1