SOLUTION: Please help me solve this equation: If f(x) = ax^2 +bx + c find f(-b/2a)?

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Please help me solve this equation: If f(x) = ax^2 +bx + c find f(-b/2a)?       Log On


   

Question 824770: Please help me solve this equation: If f(x) = ax^2 +bx + c find f(-b/2a)?
Answer by josgarithmetic(39616) About Me  (Show Source):
You can put this solution on YOUR website!
That input expression looks familiar. Recognizable or not, just substitute for x in the function and evaluate or simplify as well as possible.

a%28-b%2F%282a%29%29%5E2%2Bb%28-b%2F%282a%29%29%2Bc
%28b%5E2%29%2F%284a%29-%28b%5E2%29%2F%282a%29%2Bc
%28b%5E2%29%2F%284a%29-2%28b%5E2%29%2F%284a%29%2B4ac%2F%284a%29
%28b%5E2-2b%5E2%2B4ac%29%2F%284a%29

What would you find if you complete the square on f(x) starting with your general form, and put into Standard Form? Could that tell you something about -b/(2a)?
Try it!