Question

How do you solve the following system?: `x+y=4, 2x -5y=7`

Answer 1

`y=1/7`
`x=27/7`

Explanation:

a)`x+y=4`

b)`2x-5y=7`

First multiply a) by -2:

a)`-2x-2y=-8`

b)`2x-5y=7`

Then add a) and b)

`-7y=-1 => y=1/7`

Replace y in a)

`x+1/7=4`
`x=4-1/7=27/7`