116,853 views
28 votes
28 votes
Help meeeeeeeeeeeeeeee pleaseee!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

help meeeeeeeeeeeeeeee pleaseee!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Help meeeeeeeeeeeeeeee pleaseee!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! help-example-1
User Bing Wang
by
2.7k points

1 Answer

18 votes
18 votes

For the equation F(x) = ax² + bx + c we have:

  • maximum value if a<0
  • minimum value if a>0

F(x) = -3x² + 18x + 3 ⇒ a = -3, b = 18

a < 0 ⇒ the function has a maximum value

Quadratic function has the maximum value (or minimum) at vertex of its parabola.

The maximum value is k at x=h where:
h=(-b)/(2a) and k = F(h)


h=(-18)/(2\cdot(-3))=3\\\\F(3)=-3\cdot3^2+18\cdot3+3=-27+54+3=30

Therefore:

The function has a maximum value of 30 at x = 3

User Bartlett
by
3.4k points
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