sorry, can someone please solve this for me! i keep getting a weird answer after i used the quadratic formula. solution set for the equation
-2x^2+8x-8=0
A) {-2}
B) {2}
C) {-2,2}
D) {-2, 0, 5}

Question

sorry, can someone please solve this for me! i keep getting a weird answer after i used the quadratic formula. solution set for the equation
-2x^2+8x-8=0
A) {-2}
B) {2}
C) {-2,2}
D) {-2, 0, 5}

anonymous · Answer

what's your "wierd" answer?

anonymous · Answer

or maybe im solvign ti wrong because i get a negative answer inside the radical =P

unklerhaukus · Answer

$$x=\frac{-8\pm \sqrt{(-8)^2-4(-2)(-8)}}{2(-2)}$$

anonymous · Answer

that's prolly it...
you can also factor out a -2 first to simplify the equation.

unklerhaukus · Answer

$$\sqrt{(-8)^2-4(-2)(-8)}=64-64=0$$

unklerhaukus · Answer

*$$=\sqrt{64-64}=\sqrt0=0$$
the discriminant is zero

unklerhaukus · Answer

so $$x=\frac{-8}{-4}=2$$

anonymous · Answer

alright, got it. thanks!