Question

How do solve the following linear system?: `x= y - 11 , 8x + 3y= -9`?

Answer 1

`x=-42/11 and y=79/11`

Explanation:

`x=y-11`
`implies x-y=-11...............(i)`
`8x+3y=-9........(ii)`
Multiply `(i)` by `3` and add in `(ii)`
`implies 3x-3y=-33`
`+8x+3y=-9`
By addition we have
`11x=-42`
`implies x=-42/11`
Put `x=-42/11` in `(i)`
`implies -42/11-y=-11`
`implies -42-11y=-121`
`implies 11y=79`
`implies y=79/11`