i beg please help worth 40 points and ill give brainliest if answered right with shown work please help


1:
y = 2x
x + y = 6
3x = 6
x= 2
y = 4
2:
y = 2x - 5
x + y = 4
x + 2x - 5 = 4
x + 2x = 9
3x = 9
x = 3
y = 1
3:
x + y = 7
2x - y = 5
x = 7 - y
2x = 14 - 2y
14 - 2y - y = 5
- 9 = - 3y
3y = 9
y = 3
x = 4
4:
x + 9y = - 6
2x - 9y = 15
9y = 2x - 15
x + 2x - 15 = - 6
3x = 9
x = 3
y = - 1
5:
x + 2y = 4
y = 2x + 7
2y = 4x + 14
x + 4x + 14 = 4
5x = - 10
x = - 2
y = 3
6:
x - 4y = 16
y = 1 - x
4y = 4 - 4x
x - 4 + 4x = 16
5x = 20
x = 4
y = -3
7:
4x - y = 10
x + y = 5
y = 4x - 10
x + 4x - 10 = 5
5x = 15
x=3
y = 2
8:
2x + y = 10
3x = y
y = 10 - 2x
10 - 2x = 3x
10 = 5x
x = 2
y = 6
9:
-5x - y = 20
y = 3x
y = - 5x - 20
-5x - 20 = 3x
8x = - 20
2x = - 5
x = - 2.5
y = - 7.5
10:
2x - y = -1
x = 17 - 3y
y = 2x + 1
3y = 6x + 3
17 - 6x - 3 = x
14 = 7x
x = 2
y = 3
11:
3x + y = 3
y = 2x - 7
y = 3 - 3x
3 - 3x = 2x - 7
10 = 5x
x = 2
y = - 3
12:
2x + 3y = 17
3x - 2y = - 0.5
2y = 3x + .5
y = 1.5x + .25
3y = 4.5x + .75
2x + 4.5x + .75 = 17
16.25 = 6.5x
16.25 / 6.5 = x
x = 2.5
y = 4
13:
x - 2y = 5
3x + 2y = 23
3x = 15 + 6y
15 + 6y + 2y = 23
8 = 8y
x = 7
y = 1
14:
2x = 5y + 8
3x + 2y = 31
x = 2.5y + 4
3x = 7.5y + 12
7.5y + 12 + 2y = 31
9.5y = 19
y = 19 / 9.5
x = 9
y = 2
took a lot of time so please give brainliest