Question

determine where the following two intersect x^2+y^2=13 and y=x^2-1

Answer 1

y=sprroot of 13-x^2
sprrt13-x^2=x^2-1
13-x^2=x^4-2x^2+1
x^4-x^2-12=0

(x^2-4)(x^2+3)=0

x=2
x=-2
x=0+(i)sqrot3