Infinite they’re all multiples, so they are the same line
Answer:
36
Step-by-step explanation:
The maximum height is the y-coordinate of the vertex
given a quadratic in standard form : ax² + bx + c : a ≠ 0
then the x-coordinate of the vertex is
= - 
y = - x² + 20x - 64 is in standard form
with a = - 1, b = 20 and c = - 64, hence
= -
= 10
substitute x = 10 into the equation for y
y = - (10)² + 20(10) - 64 = 36 ← max height
Slope is .5/5
B) the longer you talk on the phone, the more it’s going to cost
C) .50 cents
D)30 minutes