To find when their costs will be same, we can set them equal to each other.
While writing the equation, we need to take into account that one plan has a base payment of 75 no matter how much Justin drove. And there are changeable values which are effected by the x, the miles driven by Justin.
So the equation is [tex]0.80x + 75 = 0.90x[/tex]
When we subtract [tex] 0.80x [/tex] from both sides: [tex]0.10 \times = 75[/tex]
Divide both sides by [tex] 0.1 [/tex]: [tex]x = 750[/tex]
He needs to drive 750 miles to make 2 plans' cost equal.
