Garis melalui titik(3,1)tegak lurus garis y=-2x+5

y=-2x+5 => y= mx+c maka m1 = -2
m2 = -1/m1 = -1/-2 = 1/2

y-y1 = m(x-x1)
Y-1 = 1/2(x-3)
2y-2 = x-3
2y+x = -1

Maaf kalo salah