a lines equation is generally
mx+b
where m is the slope (-2/15)
and b is the y intercept
point: (-5,5)
y = mx +/- b
5 = -2/15 - 5 (plugging in)
multiply b by the numerator
5 = 10/15
multiply y by the denomenator
75/15 - 10/15
subtract ^
65/15 (4.33 when calculated)