melalui titik (-2,-1) tegak lurus dengan garis yg melalui titik (-5,-4) dan (0,-2)

[/tex]m1 = \frac{y2-y1}{x2-x1} = \frac{-2-(-4)}{0-(-5)} = \frac{-2+4}{0+5} = \frac{2}{5} [/tex]

[tex]m2 = \frac{5}{2} X -1 = \frac{-5}{2} [/tex]

y-y1 = m(x-x1)
y-(-1) = \frac{-5}{2} (x-(-2))
y+1 = \frac{-5}{2} (x+2)
y+1 = \frac{-5}{2} x + \frac{-10}{2} [/tex]
y+1 = \frac{-5}{2} -5[/tex]
y = \frac{-5}{2} - 5 + 1
y = \frac{-5}{2} - 4[/tex]

cari gradiennya dulu

m = y2 - y1 / x2 - x1
= -2 - (-4)
----------
0 - (-5)
= 2/5

terus

m( x - x1 ) = y - y1
2/5 ( x - (-2)) = y - (-1)
2/5x + 2/5 . 2 = y +1
2/5x + 4/5 = y + 1
( dikali dngn 5 karena penyebutnya 5 agar tidak ada pecahan)
5 . 2/5x + 5. 4/5 = y. 5 + 1. 5
( angka yang sama di coret )
2 + 4 = 5y + 5
2x + 4 - 5y -5 = 5y -5y + 5 - 5
( 5y + 5y dicoret 5 -5 juga dicoret jadi 0 )
2x + 4 - 5y - 5 = 0
2x -5y +4 -5 = 0
2x -5y -1 = 0