Question 131220
X/4-X+4/5=1
(X-4X)/4+4/5=1
-3X/4=1-4/5
-3X/4=1/5 NOW CROSS  MULTIPLY.
-15X=4
X=4/-15
X=-4/15 ANSWER.
PROOF:
(-4/15)/4-(-4/15)+4/5=1
(-4/15)(1/4)+4/15+4/5=1
-1/15+4/15+12/15=1
15/15=1
1=1