SOLUTION: i am trying to find the y coordinate of the vertex. the x is -2 and when i plug it in to the equation i get 3(-2)^2+12(-2)+8 =-28, but the answer is supposed to be -4 can someon

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: i am trying to find the y coordinate of the vertex. the x is -2 and when i plug it in to the equation i get 3(-2)^2+12(-2)+8 =-28, but the answer is supposed to be -4 can someon      Log On


   

Question 229396: i am trying to find the y coordinate of the vertex. the x is -2 and when i plug it in to the equation i get
3(-2)^2+12(-2)+8 =-28, but the answer is supposed to be -4 can someone tell me what i am doing wrong?
Answer by rfer(16322) About Me  (Show Source):
You can put this solution on YOUR website!
I think you lost track of a sign some where.
3(-2)^2+12(-2)+8=
3(+4)-24+8=
12-24+8=
20-24=-4