tentukan persamaan garis yg melalui titik -1,5 bergradien -1/2

y-y1 = m(x-x1)
y-5 = -1/2 (x-(-1))
y-5 = -1/2 x -1/2
y + 1/2 x = 5 - 1/2
y + 1/2 x = 9/2
.....atau bisa dikalikan 2 .....menjadi:
2y + x = 9

Dik : gradien (m) = -1/2
x1 = -1
y1 = 5

Dit : Persamaan garis

y - y1 = m (x - x1)
y - 5 = -1/2 (x + 1)
2y - 10 = -(x + 1)
2y - 10 = -x - 1
x + 2y - 9 = 0 atau
2y = -x + 9
y = -1/2 x + 9/2