Question

How do you solve 3x+4y=2 and x-y+6?

Answer 1

This is presumably meant to be simple pair of linear simultaneous equations easily solved. The problem is the second one isn't equation; let's guess about what equation was meant:

`3x + 4 y = 2`

`x - y = 6`

Multiplying that equation by `4,`

`4x - 4 y = 24`

Adding to the first equation,

`7x = 26`

`x = 26 / 7`

Multiplying the second equation by three:

`3x - 3y = 18`

Subtracting from the first,

`7y = -16`

`y = - 16/7`

Check:

`x-y = 26/7 - -16/7 = 42/7 = 6 \quad \sqrt{}`

`3x + 4y = 1 7 (3(26) + 4(-16)) = 2 \quad \sqrt{}`

Remember we had to guess the equation to start, so this might not be the exact problem the student is trying to answer.