tolong bantu jawab ya butuh banget

1a) x + y = 5
2x + y = 8
------------------(-)
- x = - 3
x = 3
x + y = 5
3 + y = 5
y = 5 - 3
y = 2
ttk potong = (3,2)

b) x + y = 5
x + 3y = 3
-----------------(-)
- 2y = 2
y = - 1
x + y = 5
x - 1 = 5
x = 5 + 1
x = 6
ttk potong = (6,-1)

2a) 3x + 3y - 6 = 0
3y = - 3x + 6
m = - 3/3 = - 1
c = 6

b) 5x - y + 1 = 0
- y = - 5x - 1
m = - 5/-1 = 5
c = - 1

3) y - y1 = m (x - x1)
y + 4 = 6 (x + 1)
y = 6x + 6 - 4
y - 6x = 2

4) (y - y1) / (y2 - y1) = (x - x1) / (x2 - x1)
(y - 5) / (3 - 5) = (x + 3) / (2 + 3)
(y - 5) / - 2 = (x + 3) / 5
5 (y - 5) = - 2(x + 3)
5y - 25 = - 2x - 6
5y + 2x = - 6 + 25
5y + 2x = 19

5) 2x + 5y - 1 = 0
5y = - 2x + 1
m = - 2/5
syarat sejajar m1 = m2 = - 2/5
y - y1 = m (x - x1)
y - 3 = - 2/5 (x - 2)
y = - 2/5 x + 4/5 + 3 (dikalikan 5 utk menghilangkan penyebut)
5y = - 2x + 4 + 15
5y + 2x = 19