Question

(1/2 xy- 3/4 ab) + (-3/4 xy +1/2 ab)

Answer 1

(1/2 xy- 3/4 ab) + (-3/4 xy +1/2 ab) primero suprimimos los paréntesis y luego reducimos términos semejantes:
(1/2 xy- 3/4 ab) + (-3/4 xy +1/2 ab)=
=1/2xy-3/4ab-3/4xy+1/2ab
=-1/4xy+1/4ab