#1.
45 * 3 = 135
303 - 135
he charged 6 times his hourly rate (which would be 6x)
6x = 168
168/6 would be 28
so x = 28
which would be $28 per hour.
#2.
3n + 12 - 5n = 22
Three (3) times (multiplication) a number (n) plus (addition) 12 minus (subtraction) 5 times (multiplication) the same number (n) is (equal) 22
Combine like terms (which would be 3n and -5n in this equation)
-2n + 12 = 22
Subtract 12 from both sides which would leave you with -2n = 10
then you divide so -2n/10 = -5
so n = -5
the number would be -5