NOTE: There's more than one way to skin a cat.
#(12x-5)/(6x+3)=2-5/x#
Step 1: multilply both sides by #x#
#x*((12x-5)/(6x+3))=(2-5/x)*x#
#(12x^2-5x)/(6x+3)=2x-5#
Step 2: multiply both sides by #(6x+3)#
#6x+3*((12x^2-5x)/(6x+3))=(2x-5)*(6x+3)#
#12x^2-5x=12x^2+6x-30x-15#
Step 3: simplify
#-5x=-24x-15#
#19x=-15#
#x=-15/19#
Step 4: check your answer for #x#
#(12x-5)/(6x+3)=2-5/x#
#(12*(-15/19)-5)/(6*(-15/19)+3)=2-5/(-15/19)#
#((-180/19)-(95/19))/((-90/19)+(57/19))=2+5*(19/15)#
#(-180-95)/(-90+57)=2+19/3#
#(-180-95)/(-90+57)=6/3+19/3#
#275/33=25/3#
#11# goes into #275# #25# times and #11# goes into #33# #3# times
#25/3=25/3#