A hovercraft takes off from a platform.
Its height (in meters), xxx seconds after takeoff, is modeled by:
h(x)=-2x^2+20x+48h(x)=−2x
2
+20x+48h, left parenthesis, x, right parenthesis, equals, minus, 2, x, squared, plus, 20, x, plus, 48
What is the maximum height that the hovercraft will reach?

45 minutes

step-by-step explanation:

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15