How do you find the equation of perpendicular lines?

Question

find the equation of the line that is perpendicular to 4y+x+40=O that passes through the point (1/2,0) 

Answer 1

Find the slope of 4y+x+40=0

                        4y=-x-40

                        y=-x/4 -10

So the slope=-1/4

the slope of the perpendicular line is 4

the equation is y-y₁=m(x-x₁)

                     y-0=4(x-1/2)

                      y=4x-2