Answer:
7x+11
Step-by-step explanation:
Drop the parentheses and combine 13x and -6x which is the same as 13x-6x and it equals 7x. do the same with -4 and 15 which you can switch around (because we're adding) and make it 15-4 and it equals 11. Combine our two answers of 7x and 11 and get 7x+11
