We have a system of linear equations:
[tex]\begin{gathered} x=-4y-1 \\ 4x-3y=91 \end{gathered}[/tex]
We have to solve it by substitution.
The first equation is giving us the equation to substitute x in the second equation and solve for y:
[tex]\begin{gathered} 4x-3y=91 \\ 4(-4y-1)-3y=91 \\ -16y-4-3y=91 \\ -19y=91+4 \\ -19y=95 \\ y=\frac{95}{-19} \\ y=-5 \end{gathered}[/tex]
Now, we can use the first equation to solve for x:
[tex]\begin{gathered} x=-4y-1 \\ x=-4(-5)-1 \\ x=20-1 \\ x=19 \end{gathered}[/tex]
Answer: x=19 and y=-5
