SOLUTION: For the function, the vertex of the graph is given. Find the unknown coefficients. y=x^2+bx+c; (-4,5)

Algebra ->  Functions -> SOLUTION: For the function, the vertex of the graph is given. Find the unknown coefficients. y=x^2+bx+c; (-4,5)       Log On


   

Question 1125818: For the function, the vertex of the graph is given. Find the unknown coefficients.
y=x^2+bx+c; (-4,5)
Found 2 solutions by ikleyn, josgarithmetic:
Answer by ikleyn(52864) About Me  (Show Source):
You can put this solution on YOUR website!
.
From the condition,  y = a*(x+4)^2 + 5 = ax^2 + 8ax + 16a + 5.


Comparing coefficients, you conclude that


    a= 1, b= 8,  c= 21.


Answer by josgarithmetic(39627) About Me  (Show Source):
You can put this solution on YOUR website!
%28x%2B4%29%5E2%2B5=x%5E2%2Bbx%2Bc-------left side is in "vertex" form and right side is the variable quadratic trinomial. Multiply the left side and simplify. Compare terms.