I guess PT and QT are line segments where the lines share a common point T.
Since there's no picture we have to guess what the relationship between the line segments is. If T is the midpoint of the straight line PQ, then PT=QT so 4x-6=3x+4, x=10. So that's one possibility.
If Q is the midpoint of PT then PQ=QT, and PQ=PT-QT=4x-6-(3x+4)=x-10, so x-10=4x-6, -4=3x, making x negative which would make PQ and QT both negative which is impossible, so we can reject this solution.
If P is the midpoint of QT then PQ=PT, and PQ=QT-PT=3x+4-(4x-6)=10-x, so 10-x=4x-6, 16=5x, making x=16/5 or 3.2. This is another possible solution, but its not a "nice" one since we have fraction 16/5 as the answer.
I think the expected answer could be x=10, the first solution.