Hiroto spends $68 on ebooks and paperback books combined . Each ebook he buys costs $12 . If hiroto buys x e-books and y paperback books, which of the following equations best model's the situation ?

(23*2)-12=x     x=34

step-by-step explanation:

step-by-step explanation:

1

i am not sure :

step-by-step explanation:

step-by-step explanation:

the ratio of red paint to blue paint is always 9/7. that means that, whatever x's value, (4x+12)/(4x-4) has that same ratio. so, set up an equation and cross-multiply to solve for x:

9/7 = (4x+12)/(4x-4)

9(4x-4) = 7(4x+12)

36x - 36 = 28x + 84

8x - 36 = 84

8x = 120

x = 15