1) [tex]y = 30x - x^2
y = -x^2+30x (y = ax^2+b)[/tex]
[tex]x = -b/2a = -30/2(-1) = 15[/tex]
[tex]y = -(15)^2+20(15)
y = -225+450
y = 225[/tex]
So, 15 as the width would give us the maximum area for the painting.
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2) The maximum height your feet will be above the ground is 2.25 ft.
No, you wouldn't be able to dunk the ball because the maximum height you can jump is 2.25, but you need to jump 2.5 ft to dunk.