Question

I’m not sure how figure this out :/ I’m getting so frustrated.

Answer 1

System of equations

We want to solve the following system of equations:

`\begin{gathered} x+2y=-20 \\ x+3y=-27 \end{gathered}`

We want to combine them. This means that we want to add them by columns:

we want to add the terms with x on one hand,

the terms with y on the other hand,

and the numbers.

If we leave the equations as they are and combine them, we would have:

We can obtain a better result if we multiply the first equation by -1, and combine them after that:

`\begin{gathered} x+2y=-20 \\ \downarrow \\ -1(x+2y)=-1(-20) \\ -x-2y=20 \end{gathered}`