Diketahui persamaan garis:

garis

• ax + by + c = 0 → m = -a/b

• y = mx + c

gradien (m)

• sejajar → m1 = m2

• tegaklurus → m1 × m2 = -1

(i) 2y = x – 10

y = x/2 – 10/2 = 1/2 x – 5

m = 1/2

(ii) y = 2x – 3 → m = 2

(iii) y = -2x + 11 → m = -2

Pernyataan yg benar → B

garis (1) dan (3) saling tegaklurus

m1 = 1/2

m2 = -2

m1 × m2 = 1/2 × (-2) = -1 → saling tegaklurus