9X/4-X/4=8X/4=2X and 2X+2X=4X, and 4X-7 is the result of the first expression which is the same as the second expression. Therefore the two expressions are equivalent and the second one is a simplified version of the first. Tran is right.
If we put X=4 into both we get -1-7+9+8=9 and 4X-7=16-7=9. So that’s correct.
If we put X=0 into both we get -7. So by substitution we show that the two expressions are equivalent.