Question

How do you solve the system of equations `2y = 10-7x` and `2x=20-2y`?

Answer 1

Solve for `x`, then `y` using elimination.

`x = -2, y = 12`

Explanation:

First, move `x` and `y` to the same side of the equation so they are on top of each other. Make sure to watch your signs. Add `7x` to the top and add `2y` to the bottom.

`7x + 2y = 10`
`2x + 2y= 20`

Multiply bottom equation by `-1` to eliminate `y`.

`7x + 2y = 10`
`-2x - 2y = -20`

Add the bottom equation to the top. You're left with only `x`.

`5x = -10`

Solve for `x`, then plug `x` into either of the original equations to get `y`.

`x = -2, y = 12`