The length of the two pieces is given: 10 and x-2.
The two pieces' lengths tally up to 2x-3.
So, if we put the pieces together, we must obtain the total:
[tex]10+x-2 = 2x-3[/tex]
[tex]x+8=2x-3[/tex]
[tex]x=11[/tex]
So, GF is x-2, i.e. 11-2=9
