tentukan persamaan garis (3,6) dan (4,2)

pers garis :
( y - y1 ) / ( y2 - y1 ) = ( x - x1 ) / ( x2 - x1 )
( y - 6 ) / ( 2 - 6 ) = ( x - 3 ) / ( 4 - 3)
( y - 6 ) / - 4 = ( x - 3) / 1
1 ( y - 6 ) = - 4 ( x - 3)
y - 6 = - 4x + 12
y + 4x = 12 + 6
y + 4x = 18