standard form is ax+by=c, we like a and b to be integers, we also like a to be positive
basically get x and y on one side
so
y-4=(3/4)(x+8)
distribte the 3/4
y-4=(3/4)x+6
minus 3/4x from both sides
-(3/4)x+y-4=6
add 4 to both sides
(-3/4)x+y=10
times both sides by -4
3x-4y=-40