In order to do these, simply translate the sentence mathematically.
1) x-15=7
2)3x+4=13
3)x+x+2+x+4=51
Hope this helped :D. Comment below if you have any questions!
Well first I would subtract 7 because the seven books aren’t in the cartons, which will give you 120. Then you divide by 10 to get 12, the amount of cartons
x-0.1x=36
where x is the original price
0.1x is the discount (10% of the original price)
36 is the price paid
x-0.1x=36
0.9x=36
----- ----
0.9 0.9
x=40
The original price is $40.00
