Question

How do you solve `7x+y= 11` and `3x+2y= -11` using substitution?

Answer 1

`x = 3 and y =-10`

Explanation:

Rearrange the first equation to get:

`y = 11 - 7x`

Substitute this into the second equation:

`3x + 2(11 - 7x) = -11`

Expand the bracket:

`3x + 22 - 14x = -11`

`22 - 11x = -11`

`33 = 11x`

`x =3`

Now substitute `x = 3` into any of the three equations to find `y`:
`y = 11 - 7x` `=>` `y = 11 - 21`

`y =-10`