Denise G. answered 04/17/19
Algebra, College Algebra, Prealgebra, Precalculus, GED, ASVAB Tutor
f (x) = a(x - h)2 + k, where (h, k) is the vertex of the parabola
Using the vertex of (1,5), we can get the following
f (x) = a(x - 1)2 + 5
Next, we can plug in the other point given (5,0) for (x,y) and solve for a
0 = a(5 - 1)2 + 5
Simplify the parenthesis
0 = a(4)2 + 5
Simplify the exponent
0=16a+5
Subtract 5 from both sides
0-5=16a+5-5
Simplify
-5=16a
Divide both sides by 16
-5/16=16a/16
Simplify
-5/16 = a
Now that we have a we can plug it into the equation for the final answer
f (x) = -5/16(x - 1)2 + 5