None of the offered choices is correct.
f(3) = 0.02·2³ = 0.02·8 = 0.16
f(8) = 0.02·2⁸ = 0.02·256 = 5.12
Then the average rate of change is
... (f(8) - f(3))/(8 - 3) = (5.12 -0.16)/5 = 4.96/5 = 0.992
Since both equations are equal to y you can just make them equal to each other, like this 3x + 7 = x - 9. From there isolate the varible x on one side so that the solution will be on the other side of the equation. I'll do the steps too for you.
3x + 7 = x - 9
2x + 7 = -9
2x = -16
x = -8
Hope this helps :)
.008 is the answer you are looking for :)
For this problem, you're going to need to use trig. More specifically, you need to use the tangent function:
tan (value) = opposite/adjacent
tan 75 = opposite/8 (Here, the opposite side is the length of the ladder)
8 * tan 75 = opposite
29.8564065 = opposite
So, the ladder is 29.9 feet.