Instead of using an = sign we use 
becuase its less than or equal to 100 dollars.
The equation of the line is y=10x+7
sub in 100 for y and the inequallity sign
10x+7100
solve so x is isolated
10x93
x9.3
technically the answer is 9 because you cant buy a fraction of a CD
The equation of the line is y=10x+7
sub in 100 for y and the inequallity sign
10x+7
solve so x is isolated
10x
x
technically the answer is 9 because you cant buy a fraction of a CD