Subtract #color(red)(11/30)# from each side of the equation to solve for #x# while keeping the equation balanced:
#x + 11/30 - color(red)(11/30) = 9/10 - color(red)(11/30)#
#x + 0 = 9/10 - color(red)(11/30)#
#x = 9/10 - 11/30#
To subtract the fractions on the right side of the equation multiply #9/10# by the appropriate form of #1#, #(3/3)# to put each fraction over a common denominator:
#x = (3/3 xx 9/10) - 11/30#
#x = 27/30 - 11/30#
#x = (27 - 11)/30#
#x = 16/30#
#x = (2 xx 8)/(2 xx 15)#
#x = (color(red)(cancel(color(black)(2))) xx 8)/(color(red)(cancel(color(black)(2))) xx 15)#
#x = 8/15#
