3b=2+a

3a-b=2+a+2b

2 answers

What about it? Are we solving?

The first:
3b=2+a ----> a = 3b - 2

The second:
3a-b=2+a+2b
2a - 3b = 2
now sub in the first,
2(3b-2) - 3b = 2
6b - 4 - 3b = 2
3b = 6
b = 2, then in a = 3b-2 ,
a = 4
First equation:

3 b = 2 + a

Subtract 2 to both sides

3 b - 2 = a

a = 3 b - 2

Second equation:

3 a - b = 2 + a + 2 b

Subtract a to both sides

2 a - b = 2 + 2 b

Add b to both sides

2 a = 2 + 3 b

2 a = 3 b + 2

Since: a = 3 b - 2
replace a with 3 b - 2 in this equation

2 ( 3 b - 2 ) = 3 b + 2

6 b - 4 = 3 b + 2

Subtract 3 b to both sides

3 b - 4 = 2

Add 4 to both sides

3 b = 6

b = 6 / 3

b = 2

Put this value in:

a = 3 b - 2

a = 3 • 2 - 2

a = 6 - 2

a = 4