To find the equation, identify the slope and the y-intercept.
The slope is the coefficient to the variable. When you see the word 'per', you know that 2 is the slope, as she is paying 2 dollars per movie. This, in mathematical terms, is represented as 2x.
The y-intercept is the amount she starts off with. She gets 5 for free, so the y-intercept is +5.
The equation is [tex]c = 2m+5.[/tex]
To solve for c = 50, plug 50 in and subtract 5 from both sides:
[tex]45 = 2m[/tex]
m = 22.5
