Let's solve each system of equations and find the correct matches:
1. System: \( \begin{array}{c} y=x+2 \\ 5x-4y=-3 \end{array} \)
- Solution: \( (2, 4) \)
2. System: \( \begin{array}{c} 3x-8y=24 \\ y=x-8 \end{array} \)
- Solution: \( (10, 2) \)
3. System: \( \begin{array}{c} y=5x-9 \\ -2x-3y=-7 \end{array} \)
- Solution: \( (3, 9) \)
4. System: \( \begin{array}{c} -4x+y=6 \\ y=7x-6 \end{array} \)
- Solution: \( (2, 10) \)
5. System: \( \begin{array}{c} y=2x+3 \\ y=-2x+15 \end{array} \)
- Solution: \( (-5, 7) \)
6. System: \( \begin{array}{c} x+y=75 \\ 10x+y=48 \end{array} \)
- Solution: \( (8, 0) \)
Now, matching the solutions to the given options:
- \( A:(-3,78) \) does not match any solution.
- \( R:(2,1) \) matches the solution for system 1.
- \( G:(3,9) \) matches the solution for system 3.
- \( U:(-5,7) \) matches the solution for system 5.
- \( S:(8,0) \) matches the solution for system 6.
- \( B:(2,10) \) matches the solution for system 4.
Therefore, the answer to the riddle "WHAT DO YOU CALL YOUR FRIENDS IN MATH CLASS?" is \( \frac{2}{1} \) or simply \( 2 \).
