#(a+3)/a-6/(5a)=1/a#
#:.(a+3)/a-1/a=6/(5a)#
#:.(a+3-1)/a=6/(5a)#
multiply L.H.S and R.H.S by #5a#
#:.(5cancela)^color(green)1/1 xx (a+3-1)/cancela^color(green)1=6/cancel(5a)^color(green)1 xx cancel (5a)^color(green)1/1 #
#:.5(a+3-1)=6#
#:.5(a+2)=6#
#5a+10=6#
#:.5a=6-10#
#:.5a=-4#
#:.color(blue)(a=-4/5#
substitute #color(blue)(a=-4/5#
#:.(-(4/5)+3)/(-4/5)-6/(5(-4/5))=1/(-4/5)#
#:.(-4/5+15/5)/(-4/5)-6/(-20/5)=1 xx -5/4#
#:.(11/5)/(-4/5)-6/-4=-5/4#
#:.11/cancel5^1 xx -cancel5^1/4=-5/4#
#:.11/-4-6/-4=-5/4#
#:.color(blue)(5/-4=5/-4#