First, multiply each side of the equation by #color(red)(36)color(blue)(d)# to eliminate the fractions while keeping the equation balanced:
#color(red)(36)color(blue)(d) xx 10/36 = color(red)(36)color(blue)(d) xx 55/d#
#cancel(color(red)(36))color(blue)(d) xx 10/color(red)(cancel(color(black)(36))) = color(red)(36)cancel(color(blue)(d)) xx 55/color(blue)(cancel(color(black)(d)))#
#10d = color(red)(36) xx 55#
#10d = 1980#
Now, divide each side of the equation by #color(red)(10)# to solve for #d# while keeping the equation balanced:
#(10d)/color(red)(10) = 1980/color(red)(10)#
#(color(red)(cancel(color(black)(10)))d)/cancel(color(red)(10)) = 198#
#d = 198#