Diketahui fariis p melalui(-2,4) dan(-4,1) serta melalui (3,a) dan (5,-1) Pertanyaan : tentukan nilai a agar garis q sejajar dengan garis p

m : gradien
m = (y2 - y1) / (x2 - x1)
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mp : gradien garis p
mp = (1 - 4) / (-4 - (-2))
mp = -3/-2
mp = 3/2

mq = (-1 - a) / (5 - 3)
mq = (-1 - a)/2

syarat sejajar
mp = mq
(-1 - a)/2 = 3/2
-1 - a = 3
a = -1 - 3
a = -4