The given regression shows the relationship between the numbers of car washed(x) and the amount earned for charity(y).
y = 10x + 20
We are to calculate the amount of charity if 50 cars are washed. Number of cars are represented by x, so by substituting x = 50 in above equation we can find the amount of charity that is earned by washing 50 cars.
y = 10(50) + 20 = $ 520
Thus, the charity can earn $520 if 50 cars come in for a wash.
X-2=27
is this a good equations
Let 
be the two numbers. We have two pieces of information:
(the difference between the two numbers is 2)
(their product is 224)
From the first equation, we can deduce 
If we plug this expression in the second equation, we have
If you solve this equation with the usual quadratic formula you get the solutions
So, you have the following couple of solutions, recalling that x is 2 more than y:
