Help solving these system of equations please

1.
x/2 + y/5=4/5
x/6 - y/2 = 5/6

2.
y=x+3
x/2-y/5=3

3.
2x-5y=9
x-3=0

1)
x/2 + y/5=4/5
find the LCD: 10
5x/10 + 2y/10 = 8/10
multiply both sides by 10
5x + 2y = 8
y = (8 - 5x) /2 [1]

x/6 - y/2 = 5/6
multiply both sides by 6
x - 3y = 5 [2]

sub [1] into [2]
x - 3[(8 - 5x) /2] = 5
x - (24 + 15x)/2 = 5
multiply both sides by 2
2x - 24 + 15x = 10
put x by itself
17x = 34
x = 34/17
x = 2

sub x = 2 into [1] to solve for y
y = (8 - 5x) /2
y = (8 - 10)/2
y = -1

ANSWER: x = 2, y = -1 (2, -1)

2)
y = x + 3 [1]
x/2 - y/5=3
multiply both sides by 10 (get rid of denominators)
5x - 2y = 30 [2]
sub [1] into [2]
5x - 2(x + 3) = 30
3x = 36
x = 12
sub x= 12 into [1]
y = 12 + 3
y =15


ANSWER: x = 12, y = 15

3)
x - 3 = 0, x = 3

sub x= 3 into 2x - 5y = 9, solve for y
2(3) - 5y = 9
6 - 5y = 9
5y = -3
y = -3/5 (or -0.6)

ANSWER: x = 3, y = -0.6

Hope this was helpful :)