Persamaan garis melalui titik (5,-3) dan tegak lurus garis y= -7x + 5 adalah...

m = -7
karena tegak lurus maka :
m1 x m2 = -1
-7 x m2 = -1
m2 = 1/7
pers garis luris = (y-y1) = m (x-x1)
= y +3 = 1/7 (x-5)
= y +3 = 1/7x -5/7
semua dikali 7
7y +21=x-5
pers garis : x-7y+26=0

y = -7x + 5

maka..

m1 = -7
tegak luru
m1 x m2 = -1
-7 x m2 = -1
m2 = -1 / -7
m2 = 1/7

y - y1 = m (x - x1)
y + 3 = 1/7 (x - 5)
7 (y + 3) = x - 5
7y + 21 = x - 5
7y = x - 5 - 21
7y = x - 26
y = 1/7x - 26/7