Answer:
C. 50
Step-by-step explanation:
x+y=90
x=2y-30
90-y=2y-30
3y=120
y=40
90-40= 50
<em>t</em> = 0 belongs to the interval [-3, 3] (since -3 ≤ 0 ≤ 3 is true), so use the middle function to evaluate <em>h</em> (0):
<em>h</em> (0) = 0 × (0 + 4) = 0