Use a=-2, b=-3 and c= 6 to write an expression that has a value of 6

Alaptop computer is purchased for $1350 . after each year, the resale value decreases by 30% . what will the resale value be after 5 years?

Five dinosaurs go for a walk and come across some lovely chicken wings. their names are rexy, bronto, steggy, paly, and terry. there are exactly 5 dozen wings(equal enough for each dino to have a dozen right? ); however, terry is on a diet and he only eats 6 wings. if paly eats 2 more than terry, steggy eats 4 more than paly, and bronto and rexy eat the same amount because they are really hungry from not eating all day, how many chicken wings did each dino eat?

Solve: 3x+y=6 4x-2y=18 show all work !