Melalui titik A(-2,1) dan sejajar garis y= -×+9

y = -x+9
by = ax+c
m = a/b
m = -1

titik A (-2,1)
x1 = -2
y1 = 1

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