Create an equation for the total costs of driving x miles: 3.50 + 2.50x
since Sasha has $37, the equation would become: 3.50 + 2.50x = $37
subtract 3.50 from both sides: 2.50x = 33.50
divide 2.50 on both sides: x = 13.4
since the problem is asking for the greatest whole number of miles, you have to round down and the answer would be: 13 miles.
The formula to find the slope of a line is

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I'm not sure if my fraction looks right, so I'll add it in a separate attachment too.
It's either A or B I'm not sure which but it is one of them thats correct sorry if this doesn't help that much