Question 539152
What is the minimum value of the function y = 3x2 + 2x – 8?
Vextex occurs where x = -b/(2a) = -2/(-6) = 1/3
f(1/3) = 3(1/3)^2+2(1/3)-8 = (1/3) + 2/3 -8 = -7
Min at (1/3,-7)
and
The equation h(t) = 40t – 16t2 describes the height h, in feet, of a ball that is thrown straight up as a function of the time t, in seconds, that the ball has been in the air. At what time does the ball reach its maximum height? 
t = -b/(2a) = -40/(2*-16) = 5/4 seconds
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What is the maximum height?
h(5/4) = 40(5/4)-16(5/4)^2 = 50-25 = 25 ft
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Cheers,
Stan H.
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