Question

x - 9y = 20 -8x + 18y = 2

Answer 1

The given system is

$\begin{cases}x-9y=20 \\ -8x+18y=2\end{cases}$

First, we multiply the first equation by 8

$\begin{cases}8x-72y=160 \\ -8x+18y=2\end{cases}$

Then, we combine the equations

$\begin{gathered} 8x-8x-72y+18y=160+2 \\ -54y=162 \\ y=\frac{162}{-54} \\ y=-3 \end{gathered}$

Now, we find x

$\begin{gathered} x-9y=20 \\ x-9(-3)=20 \\ x+27=20 \\ x=20-27 \\ x=-7 \end{gathered}$

Hence, the solution to the system is (-7, -3).