4x - 24y = 72
First subtract 4x from each side
-24y = -4x + 72
Divide each side by -24 so y is by itself
y = -4/-24x + 72/-24
To simplify -4/-24, the greatest common factor they have is -4, so divide the numerator and denominator by -4
y = 1/6x + 72/-24
To simplify 72/-24, the greatest common factor is 24, so divide the numerator and denominator by 24
y = 1/6x - 3
This is now in slope intercept form