Question

How do you solve `2x+3y=9` and `2x+y=11` using substitution?

Answer 1

The quickest way would be to subtract the second equation from the first

Explanation:

We have `2x+3y=9`
minus `2x+y=11`
leaves `cancel(2x)-cancel(2x)+3y-y=9-11`
`2y=-2->y=-1`
Now substitute that for `y`:
`2x+ (-1)=11->2x=12->x=6`

Check with the other equation:
`2xx6+3xx(-1)=12-3=9` check!