To make the LHS positive write #-(1-2x)" as "+(2x-1)# giving:
#" "(2x-1)/(x-3)" "=" "(5-x)/(2x-5)#
#" "color(green)([(2x-1)/(x-3)color(red)(xx1)]" "=" "[(5-x)/(2x-5)color(red)(xx1)])#
#color(green)([(2x-1)/(x-3)color(red)(xx(2x-5)/(2x-5))]" "=" "[(5-x)/(2x-5)color(red)(xx(x-3)/(x-3))])#
#" "((2x-1)(2x-5))/((x-3)(2x-5))" "=" "((5-x)(x-3))/((x-3)(2x-5)) #
As the denominators are the same on both sides then; if the whole equation is true then just equating the numerators to each other is also true
#" "(2x-1)(2x-5)" "=" "(5-x)(x-3) #
#" "4x^2-12x+5" "=" "-x^2+8x-15#
#" "5x^2-20x+20" "=" "0#
Divide everything by 5
#" "x^2-4x+4" "=" "0#
#" "(x-2)(x-2)" "=" "0#
#" "x" "=" "2#
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Check
#(2x-1)/(x-3)=(5-x)/(2x-5)#
LHS#->(2(2)-1)/(2-3) = 3/(-1)=-3#
RHS#->(5-2)/(2(2)-5) = 3/(-1)=-3#