Question

Please help me....

Use the zeros of the following quadratic to find the x-value of the vertex. y=x^2-4x-5


A. 5
B. 2
C. –2
D. –5

Answer 1

Factor
(x-5)(x+1)
Proof
-5+1=-4
-5*1=-5

ZPP for roots
x=5, x=-1

Find average for axis of symmetry (x of vertex)
(5+-1)/2=2

Final answer: B

PS an easier way to do this is by finding the axis of symmetry using the formula -b/2a. -(-4)/2(1)= 4/2= 2