This table shows the value of a computer as a function of time elapsed since the computer was manufactured. The value of the computer decreased exponentially throughout the five-year period. What was the average annual amount of Decrease in dollars per year over the two-year interval from t = 2 to t = 4

ok then what happened.

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