Question

How do you solve the simultaneous equations `x + 2y = 5` and `3x - 2y + 7`?

Answer 1

`(x,y) = (3,1)`

Explanation:

[1]`color(white)("XXXX")` `x+2y =5`
[2]`color(white)("XXXX")` `3x-2y = 7`

Adding [1] and [2]
[3]`color(white)("XXXX")` `4x = 12`

Dividing by 4
[4]`color(white)("XXXX")` `x = 3`

Substituting `3` for `x` in [1]
[5]`color(white)("XXXX")` `3 + 2y = 5`

Simplifying
[6]`color(white)("XXXX")` `y = 1`