a: =>11/12x=1/12+5/6=1/12+10/12=11/12
=>x=1
d: =>x-2/3=3/4-5/6=9/12-10/12=-1/12
=>x=-1/12+8/12=7/12
b: =>1/4x=1
=>x=4
e: =>-11/9x=-2/3-8/3=-10/3
=>x=10/3:11/9=10/3*9/11=90/33=30/11
f: =>3/2x=2-5/4=3/4
=>x=1/2
c: =>1/3:x=3/5-2/3=9/15-10/15=-1/15
=>x=-1/3:1/15=-5