Question

Solve using elimination. x − 8y = 19 9x + 8y = 11 (, )

Answer 1

`(3;-2)`

Explanation:

Let's add together the two equations

`I + II : x-8y +9x +8y = 19+11 \rightarrow 10x=30 \rightarrow x =3`

At this point I would recommend simply using the value of x in the firs equation to find y.
`3-8y=19 \rightarrow -8y=16 \rightarrow y=-2`

Or just multiply the first by 9 and subtract the second.

`9* I-II: 9x-72y-9x-8y=171-11 \rightarrow -80y=160 y=-2`