First, we need to combine the fractions in the numerator and denominator by putting the over common denominators and then adding or subtracting them:
#(1/2 + 8/7)/(3/2 - 4/7) => ((7/7 xx 1/2) + (2/2 xx 8/7))/((7/7 xx 3/2) - (2/2 xx 4/7)) => (7/14 + 16/14)/(21/14 - 8/14) => #
#((7 + 16)/14)/((21 - 8)/14) => (23/14)/(13/14)#
We can now use this rule for dividing fractions:
#(color(red)(a)/color(blue)(b))/(color(green)(c)/color(purple)(d)) = (color(red)(a) xx color(purple)(d))/(color(blue)(b) xx color(green)(c))#
#(color(red)(23)/color(blue)(14))/(color(green)(13)/color(purple)(14)) = (color(red)(23) xx color(purple)(14))/(color(blue)(14) xx color(green)(13)) = (color(red)(23) xx cancel(color(purple)(14)))/(cancel(color(blue)(14)) xx color(green)(13)) = 23/13#