As for a specific equation, I could not say. However, I can tell you how to find x!
The first thing to remember is that a straight line has a 180 degree angle.
You see on the bottom side that we have a 146 degree angle. Now look at the top side. Look closely, and you will see that the two sides are actually identical!
Don't see it? Look at the line on top between x and 56, and imagine it is not there. You see that we actually have the same 146 degree angle, just flipped right side up!
However, this angle does not say 146, but makes an extra line between them with x and 56. This means that x + 56 equals 146!
So we can find x by subtracting 56, from 146, which is... 90!
c.) $3.38
Original price = $2.60
* It is the basis of increase thus, 100%
* The increase is 30%, thus, 100% + 30% = 130%
To get the new price, simply multiply the original price to 130%
$2.60 * 130% = $3.38
Another way of solving the problem is getting the equivalent of 30% and adding it to the original price.
$2.60 * 30% = $0.78
$2.60 + $0.78 = $3.38
f(x) = 5x is linear. Just a straight line with a slope of +5. So if the intervals are both a difference of 1, then the average rate of change will be the same.
f(x2) - f(x1) over x2 - x1. That's the formula for average rate of change.
So for Section A:
f(x) = 5x, (0,1)
[f(1) - f(0)]/(1-0)
= [5(1) - 5(0)]/1
=(5)/1
=5
Do the same for section B and you'll get 5 as well.
I hope this helps you because I have no clue if my answer is right