Recall that

. So we can add twice the first equation to the second one to get

Since

, we have

so

If

, then

If

, then

So the solution set is
Yes, there was a mistake in applying the distributive property. If you have to perform

you have to multiply both terms in the parenthesis by 3, not just the first one.
So, the correct expansion would be

YOUR ANSWER IS 9
HOPE IT HELPS:)
Out of every 11 students 7 were girls. Set up the following proportion.
11/7 = 77/x Cross multiply
11x = 7*77
x = 7*77/11
x = 49
49 of the student council members were girls.
To find x, you divide both sides of the equation by 12.20. This would look like this:
12.20x/12.20 =372.10/12.20 . Then, the answer you get is 30.5, so. X=30.5