What is the x-value of the solution to the system of equations?

5x 4y = 8

2x − 3y = 17

−3
−2
4
5

The first column is what each Y value would be in the second equation, positions corresponding to the X values given. The second column is what the possible Y values are in the first equation, being +/- as we don't know what it is, but can deduce anyway.
-23/3   +/-23/4. Won't work.
-7         +/-9/2. Won't work.
-3        +/-3. Works in case of +
-7/3     +/-17/4. Won't work.

4 is the only possible solution with the full point being (4, -3) meaning the first equation is 5x+4y=8.