Question

A music store sells used cds for $5 each and buys used CDs for$1.50 each. you go to the store with $20 and some CDs to sell. you want to have at least $10 left when you leave the store. write and graph an inequality to show how many CDs you could buy and sell.
please help 20 pts! i can graph it i just need help with the equation! thanks

Answer 1

Let x be the number of CDs we buy and y the number of CDs we sell. 
Each CD sell for $1.5, then the total of money we earn is $1.5y.
Each CD bought for $5, then the total money spent is $-5x
Add the above values like this:
1.5y-5x
We have $20, add them like this:
1.5y-5x+20
Since we want to have at least $10 left when you leave the store, then 
we deduce the equation:
$1.5y-5x+20\leq 10$