How do you solve x^2+y=8 and x-2y=-6 ?

1 Answer
Jan 28, 2017

(-5/2, 7/2), (2, 4)

Explanation:

x^2+y=8
x-2y=-6
In the first equation solve for y in terms of x:
x^2+y=8 => y=8-x^2
Substitute for y in the second equation:
x-2(8-x^2)=-6 => simplify:
x-16+2x^2=-6 => add 6 to both sides and rewrite as:
2x^2+x-10=0
Solve by quadratic formula or by factoring,
(2x+5)(x-2)=0
x=-5/2 or x=2
Solve for y:
y=8-(-5/2)^2 or y=8-2^2
y=8-25/4 or y=8-4
y=7/4 or y=4
Hence the solutions are:
(-5/2, 7/2), (2, 4)