Can somebody help me?

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)

Desmond wants to sell his car that he paid $8,000 for 2 years ago. the car depreciated, or decreased in value, at a constant rate each month over a 2-year period. if x represents the monthly depreciation amount, which expression shows how much desmond can sell his car for today? \ 8,000 + 24x 8,000 - 24x 8,000 + 2x 8,000 - 2x

Which of these angles are supplementary? a. 100o and 90o b. 78o and 102o c. 54o and 146o d. 12o and 78o