Question

How do you solve `3x-y=1` and `x+y=3`?

Answer 1

I found:
`x=1`
`y=2`

Explanation:

I would isolate `x` from the second equation and substitute it into the first:
`x=3-y`
into the first:
`3(color(red)(3-y))-y=1`
`9-3y-y=1`
`-4y=-8`
`y=2`
substitute this back into the second equation:
`x=3-2=1`

Answer 2

`color(red)( x=1,y=2)`

Explanation:

Gió's method uses the method of substitution.

Here's how to do it by the method of elimination.

Step 1. Enter the equations.

[1] `3x-y=1`
[2] `x+y=3`

Step 2. Add Equations 1 and 2.**

`4x=4`

[3] `x=1`

Step 3. Substitute Equation 3 in Equation 2.

`x+y=3`
`1+y=3`

`y=2`

Solution: `x=1,y=2`

Check: Substitute the values of `x` and `y` in Equation 1.

`3x-y=1`
`3(1)-2=1`
`3-2=1`
`1=1`

It checks!

The solution is correct.