tolong dijawab pake caranya...

m = ( y2 - y1 ) / ( x2 - x1 )
m = ( - 5 + 1 ) / ( 1 - 7 )
m = - 4 / - 6
m = ⅔

sejajar m1 = m2 = ⅔

pers garis
y - y1 = m ( x - x1 )
y - 9 = ⅔ ( x - 8)
y = ⅔ x - 16/3 + 9 ( dikali 3)
3y = 2x - 16 + 27
3y - 2x = 11
- 2x + 3y = 11 ( dikali negatif)
2x - 3y = - 11 ( C )