y=mx+b
m=slope
perpendicular lines have slope that multiply to -1
y=0.5x+3
0.5 times what=-1
dvide boths sides by 0.5 aka times both sides by 2
what=-2
the equation of a line passing throug the point (x1,y1) and hving a slope of m is
y-y1=m(x-x1)
so
slope=-2
point is (2,0)
y-0=-2(x-2)
y=-2(x-2)
y=-2x+4
