f(x)=x2+2x-5
Use the quad formula a=1, b=2, c=-5
2+/-SQRT4-4*1*-5/2= 5 OR -3
oops. Forgot those pesky "-" signs:
[2+/-SQRT(4-4*1*-5)]/2
= [-2+/-SQRT(4+20)]/2
= [-2+/-2SQRT(6)]/2
= -1 +/- SQRT(6)
2+/-SQRT4-4*1*-5/2= 5 OR -3
[2+/-SQRT(4-4*1*-5)]/2
= [-2+/-SQRT(4+20)]/2
= [-2+/-2SQRT(6)]/2
= -1 +/- SQRT(6)