How do you solve the system x2+y2=5 and y=3x+5?

1 Answer
Aug 28, 2016

Solution set is (2,1) or (1,2)

Explanation:

As y=3x+5, x2+y2=5

x2+(3x+5)2=5 or

x2×9x2+2×3x×5+25=5 or

10x2+30x+20=0 or dividing by 10, we get

x2+3x+2=0 or

x2+x+2x×2=0 or

x(x+1)+2(x+1)=0 or

(x+2)(x+1)=0 i.e.

x=2 or x=1

Hence y=3×(2)+5=1 or

y=3×(1)+5=2

Hence solution set is (2,1) or (1,2)