tolong ya no4 sama 5 ajaaa. pake cara secepatnya ya . terimakasih

4a) m = ( y2 - y1 ) / ( x2 - X1 )
m = ( 7 - 4 ) / ( - 5 - 1 )
m = 3 / - 6
m = - ½
subtitusi ke salah satu titik
y - y1 = m ( x - X1 )
y - 7 = - ½ ( x + 5 )
y = - ½x - 5/2 + 7 ( dikali 2)
2y = - x - 5 + 14
2y + x = 9

b) y - y1 = m ( x - X1 )
y - 4 = ½ ( x - 1 )
y = ½ x - ½ + 4 ( dikali 2)
2y = x - 1 + 8
2y - x = 7

c) 2x - 5y = 0
- 5y = - 2x
m = - 2/-5
m = 2/5
gradien saling tegak lurus
m1 . m2 = - 1
2/5 . m2 = - 1
m2 = - 5/2
pers garis
y - y1 = m ( x - X1 )
y - 4 = - 5/2 ( x - 1)
y = - 5/2 x + 5/2 + 4 ( dikali 2)
2y = - 5x + 5 + 8
2y + 5x = 13

5) 4x - ay = 5
- ay = - 4x + 5
m = -4/-a
m1 = 4/a
3x + ( a + 1)y = 10
(a + 1 )y = - 3x + 10
m2 = - 3 / ( a + 1 )
gradien saling tegak lurus
m1 . m2 = - 1
4/a . -3/(a + 1) = - 1
4 ( - 3)
---------------- = - 1
a ( a + 1 )

- 12
-------------- = - 1
a² + a

- 12 = - 1 ( a² + a )
- 12 = - a² - a
a² + a - 12 = 0
( a + 4)( a - 3) = 0
a = - 4 atau a = 3
yg memenuhi a = 3

b) g1 ---> 4x - ay = 5 , 4x - 3y = 5
g2----> 3x + (a + 1 )y = 10 , 3x + 4y = 10
ttk potong
4x - 3y = 5 |×4
3x + 4y = 10 |×3
maka
16x - 12y = 20
9x + 12y = 30
---------------------(+)
25x = 50
x = 2
subtitusi
4x - 3y = 5
4(2) - 3y = 5
8 - 3y = 5
- 3y = 5 - 8
- 3y = - 3
y = 1
ttk potong ( 2 , 1 )

c) m = ( y2 - y1 ) / ( x² - X1 )
m = ( 1 - 0) / ( 2 - 0)
m = 1/2
subtitusi ke salah satu titik
y - y1 = m ( x - X1 )
y - 1 = ½ ( x - 2 )
y = ½ x - 1 + 1
y = ½ x
2y - x = 0