Question

The equation of a parabola in the xy-plane is given as

y= n(x + 5)(x - 3) where n is a non-zero constant. What
is the y-coordinate of the vertex of this parabola in
terms of n?
A. -18n
B. -16n
C. -15n
D. -12n

Answer 1

B

Explanation:

y=n(x+5)(x-3)

or y=n(x²-3x+5x-15)

or y=n(x²+2x-15)

=n(x²+2x+1-1-15)

=n(x+1)²-16n

y -coordinate of vertex=-16n