I tried to understand what you wrote
1+2/3 -1 1/6 I got 1/2
Let n be the first even integer, and n+2 will be the second even integer. (Why? Think 2 and 4, 2+2=4. This is the case for every consecutive even integers).
n + 3(n+2) = 54
n + 3n + 6 = 54
4n = 48
n = 12, n+2 = 14
A=πr^2s/360 multiply both sides by 360
360A=sπr^2 divide both sides by πr^2
s=360A/(πr^2)
Constant rate of change is just saying how much the x or y value is going up or down. hoped this helped :)