a, (2x-3)4=(2x-3)6
=> (2x-3)6 : (2x-3)4=1
=> (2x-3)3=
=> 2x-3=1
=> 2x=4
=> x=2
b, (3x+5)3=(3x+5)2016
=> (3x+5)2016 : (3x+5)3=1
=> (3x+5)2013=1
=> 3x+5=1
=> 3x=-4
=> x=-4/3
c, (2x+1)2015=(2x+1)2017
=> (2x+1)2017 : (2x+1)2015=1
=> (2x+1)2=1
=> 2x+1=1
=> 2x=0
=> x=0