71) 4x + 18 = 25, what is 4x - 8
First solve for x.
Subtract 18 from both sides.
4x = 7
Divide by 4 to isolate variable x.
x = 7/4
Now we find 4x - 8
4(7/4) - 8
7 - 8 = - 1, Option C
72) C =(5/9)(F - 32), solve for F
First step is to multiply both sides by 9/5, the opposite of that coefficient outside of the parenthesis, in order to cancel it out.
9/5C = F - 32
Now add 32 to both sides to isolate variable F.
9/5C + 32 = F, Option D