Question

How do you solve `5m+n=43` and `m-2n=13` using substitution?

Answer 1

`m = 9`
`n=-2`

Explanation:

`5m + n = 43 => n = 43-5m`

`m-2(43-5m )=13`
`m-86+10m =13`
`11m-86=13`
`11m=99`

`m=99/11=9`

`n = 43-5m`
`n = 43-5 times 9 =-2`

Double check:

`5 times 9 + (- 2) = 43`
`9-2times(-2)=9+4 = 13`