Christine went shopping and bought each of her eighteight nephews a gift, either a video costing $14.95 or a cd costing $16.88. she spent $131.18 on the gifts. how many videos and how many cds did she buy?

So I think you should set up an equation like this: 14.95x+16.88y=131.18 , x+y=8

so x=8-y, plug this into the original equation:
14.95(8-y)+16.88y=131.18
Evaluate: 119.60-14.95y+16.88y=131.18
Combine like terms: 119.60+1.93y=131.18
Subtract 119.60 from both sides. You get: 1.93y=11.58
Divide both sides by 1.93. You get y=6

Plug into second equation: x+y=8 ---> x+6=8 and solve for x. x=2

Christine bought 2 video games and 6 CDs. 14.95(2)+16.88(6)=131.18