Persamaan garis lurus yang melalui titik (7,-4) dan (9,6)

( y - y1 ) / ( y2 - y1 ) = ( x - X1 ) / ( x2 - X1 )
( y + 4 ) / ( 6 + 4 ) = ( x - 7 ) / ( 9 - 7 )
( y + 4 ) / 10 = ( x - 7 ) / 2
2 ( y + 4 ) = 10 ( x - 7 )
2y + 8 = 10x - 70
2y - 10x = - 70 - 8
2y - 10x = - 78 ( disederhanakan)
y - 5x = - 39

( y - y1 ) / ( y2 - y1 ) = ( x - x1 ) / ( x2 - x1 )
( y - 7 ) / ( 6 + 4 ) = ( x - 7 ) / ( 9 - 7 )
2( y - 7 ) = 10( x - 7 )
2y - 14 = 10x - 70
2y - 10x = -70-14

semoga bermanfaat