Question

Solve the system of equations 4x – 9y = 5 and 8x - y = -7 by combining the
equations.

Answer 1

x=2 and y=0.

Explanation:

Answer 2

`x=-1,\\y=-1`

Explanation:

We can write the following system of equations as given:

`\begin{cases}4x-9y=5\\8x-y=-7\\\end{cases}`.

Multiply the first equation by
`-2` then add both equations to solve for
`y`:

`\begin{cases}-8x+18y=-10\\8x-y=-7\\\end{cases},\\17y=-17,\\y=\fbox{$-1$}`.

Now plug in
`y=-1` into any equation to solve for
`x`:

`8x-(-1)=-7,\\8x+1=-7,\\8x=-8,\\x=\fbox{$-1$}`.

Verify that the solution pair
`(-1,-1)` works
`\checkmark`