Answer :
Answer: [tex]r=-5,q=2[/tex]
Step-by-step explanation:
Given
The system of linear equations are
[tex]qx-ry=18\\rx+qy=13[/tex]
It is given (-1,4) is the solution to the equations
[tex]\therefore -q-4r=18\quad \ldots(i)\\-r+4q=13\quad \ldots(ii)[/tex]
Solve the above equation we get
[tex]r=-5,q=2[/tex]