1/3+1/5+7/30=10/30+6/30+7/30=23/301-(7/9+3/4)=1-(28/36+27/36)=1-55/36=-19/365/7+5/14-3/5=50/70+25/70-42/70=33/702/11-(2/3+2/11)=2/11-2/3-2/11=-2/35/7-X=1/4 X=5/7-1/4 X=20/28-7/28 X=13/28