buatlah persamaan garis dibawah ini ! 1) melalui titik A(4,3) , B(-5,-4) 2) melalui titik A(5,-3)

Jawab :

1) m = y2 - y1/ x2 - x1 = (-4) - 3/ (-5) - 4 = -7/-9 = 7/9

y - y1 = m(x - x1)
y - 3 = 7/9(x - 4)
y - 3 = 7/9x - 7/9 . 4
y - 3 = 7/9x - 28/9
---------------------------- x 9
9. y - 3 . 9 = 7/9x . 9 - 28/9 . 9

9y - 27 = 7x - 28
9y - 27 - 7x + 28 = 0
9y - 7x + 1 = 0
7x + 9y + 1 = 0 => ax + by + c = 0


2) m = y/x = -3/5

y - y1 = m(x - x1)
y - (-3) = -3/5 (x - 5)
y + 3 = -3/5x + 3/5 . 5 = 3
y + 3 = -3/5x + 3
y = -3/5 + 3 - 3
y = -3/5x