Algebra 2 Need help with b

a. was incorrect a = -0.109569028 so...

y = -0.109569028(x + 7)² + 54

b. It's been the above vertex equation for a parabola then

set y = 40 equal to the parabolic equation, we get

40 = -0.109569028x² - 1.533966392x + 48.631117628

solve for x we get

x = -18.3036867393939 or ~ 18.3 feet

Step-by-step explanation:

y = a(x - h)² + k

(h, k) = vertex = (-7, 54)

x = h is the axis of symmetry -7

y = a(x -(-7))² + 54

y = a(x + 7)² + 54

solve for a by inputting the point (15.2, 0)

0 = a(15.2 + 7)² + 54

-54 = a(22.2)²

-54 = 492.84a

a = -54/492.84

a = -0.109569028

this is answer of 144 cubic meters