Question

How do you solve the system of equations: x+y=3, 2x-y= -3?

Answer 1

Add the equations together to get an expression in terms o) `x`, solve for `x`, substitute the solution value back into one of the equations to solve for `y`
`color(white)("XXXX")` `(x,y) = (0,3)`

Explanation:

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

Adding [1] and [2]
[3]`color(white)("XXXX")` `3x = 0`
Solve for `x`
[4]`color(white)("XXXX")` `x=0`

Substitute `0` for `x` in [1]# [5]#color(white)("XXXX")#`0 + y = 3`
Solve for `y`
[6]`color(white)("XXXX")` `y = 3`