Please answer both questions with adding your work

1-   1/3 x +3y=1

y=2/3 x-4    

solution : x=39/7 , y=-2/7

3x-2y=11

-3x-y=4   solution x=1/3, y=-5

Step-by-step explanation:

1/3 x +3y=1

y=2/3 x-4

solve by substitution for y in the first equation:

1/3 x + 3(2/3 x-4)=1

1/3 x+6/3 x-12=1

7/3 x=12+1

7/3 x=13 ⇒7x=39 ⇒x=39/7=5 4/7

y=2/3 x -4

y=2/3 (39/7)-4

y=72/21  -4

y=-4/7

second problem:

3x-2y=11

-3x-y=4    solve by elimination: add two equation to eliminate x

3x-2y-3x-y=11+4

-3y=15

y=15/-3 ⇒y=-5

substitute y in one of the equations: 3x-2y=11

3x-2(-5)=11

3x+10=11

3x=11-10

x=1/3