Answer:3 hours
Step-by-step explanation:
We are given with the equation <span>f(x) = ax3 + bx2 + cx + d
Substituting, (3,11)
</span><span>11= 27a + 9b + 3c + d
</span><span>@(5, 9)
</span><span>9 = 125 a + 25 b + 5c + d
@</span><span>(4, 10)
</span><span>10 = 64 a + 16 b + 4c + d
@inflection point, second derivative is equal to zero
</span><span>f'(x) = 3ax2 + 2bx + c
</span>f''(x) = 6ax + 2b = 0
when x is 4, 24 a + 2b = 0 or 12a + b = 0.
There are 4 equations, 4 unknowns: answer is
<span>0.5 x^3 - 6x^2 + 22.5 - 24 = 0</span>
The two labeled angles are alternate interior angles, and as such, they are the same.
From this result you can build the equation

and solve it for x: subtract 13x from both sides to get

and add 2 to both sides to get

Check: if we plug the value we found we have

So the angles are actually the same, as requested.