The 3rd one because you have to get the y-intercept also which is -6
For this case we have the following expression:

We multiply both sides by: 

We divide both sides by 216:

To divide powers of the same base, we place the same base and subtract the exponents:

Rewriting:

To multiply powers of the same base, we place the same base and add the exponents:

We know that any number raised to zero is 1, 
So, for equality to be true:

Answer:

RU is 34. To find the answer you can use a proportion. In this problem the proportion would be 60/51 = 40/x. You can then cross multiply giving you 51*40=60x. You can then solve for x which is your answer.
Area = Length x Width (A = L x W)
A = 264, W = 11, L = ?
Rewrite the equation to find L. In order to reverse multiplication, you must divide.
L = A / W
L = 264 / 11 = 24 yards