A rain barrel is 65% full. If there are 26 gallons of rain water in the barrel, how many gallons of water can the whole barrel hold?

Explanation is in the file

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If there is no number in between sets of numbers, it's going to be multiplication.
So (w+2) x (w+7)

w+2, well, evaluates into w+2.
w+7 is w+7.

We'll use the FOIL method for this.
FOIL stands for:

First
Outer
Inner
Last

Let's start with the first terms. Multiply them. 
So: w * w.
Combine both w's, and you get .

Now multiply the outer terms. 
w * 7 = 7w.

Then the inner terms. 2 and w.
2 x w = 2w.

So our current numbers are: , 7w, and 2w.
We can add 7w and 2w together.
7w + 2w = 9w.

Now multiply the last terms.
2 x 7 = 14.

So, this simplifies to 
Hope this helped!