Solve the linear system using substitution

Hello there!

3x - y = 3
-x + y = 3

We need to solve 3x - y = 3 for y

Let start by adding -3x to both sides

3x - y = 3

3x - 3x - y = 3 - 3x

-y = 3 - 3x
We cannot leave the variable with a negative sign. We must multiply both sides by -1

-y * -1= (3 - 3x)-1

y = 3x - 3

Substitute 3x -3 for y in -x+y=3

-x + y = 3

-x + 3x - 3 = 3

2x - 3 = 3

2x = 3 + 3

2x = 6

x = 6/2

x = 3

Now substitute 3 for x in y=3x -3

y = 3x - 3

y = 3(3) - 3

y= 9 - 3

y= 6

Thus,

The answer is x=3 and y=6

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