Answer:
m=1
Step-by-step explanation:
Slope is equal to the change in y over the change in x, or rise over run.
m=change in y / change in x

The equation is d=12m for amount you earn is 12 dollars per mow sesion.
12x10=120 after 10 times mowing you earned $120 (not bad)
X=750+125.75x
subtract to variable (x) on one side
x-125.75x=750+125.75x-125.75x
-124.75x=750
divide -124.75 to get variable (x) by itself
-124.75x/-124.75=750/-124.75
x=-3000/499
or
x=-6 6/499
or
x=-6.01202
85 x 3 = 255
first 2 test grades were 81 and 86:
81 + 86 = 167
Need to find the 3rd to have exact average 85:
255 - 167 = 88
So her 3rd test needs to make 88 to make average of 85
Double check: 81 + 86 + 88 = 255 = 85 + 85 + 85