Answer:
Let's write two linear equations:
For the Xbox, we have:
Price per console (you pay it only once) = $150.
Price per game = $24
Then, the total price if you buy x games, you have:
P1(x) = $150 + $24*x
For the Playstation we have:
Price per console (again yo pay it only once) = $180
Price per game = $20
So if you buy x games, the total price is:
P2(x) = $180 + $20*x.
Now, we can find the number x such that both prices are equal
P1(x) = P2(x)
$150 + $24*x = $180 + $20*x.
let's solve this for x.
$24*x - $20*x = $180 - $150
$4*x = $30
x = $30/$4 = 7.5
What does this mean?
If you buy less than 7.5 games (7 or less) then the Xbox will be cheaper, because the y-intercept is smaller.
If you buy more than 7.5 games (8 or more) then the Playstation will be cheaper, because the price per game is smaller.