a) -3xy-(2x-y+2xy)= -3xy-2x+y-2xy = -5xy-2x+y
b) 4ab+(2a-3ab)= 4ab+2a-3ab= ab+2a
c) -(3p-r)-2r= -3p+r-2r= -3p-r
d) -st-(-2t+s)= -st+2t-s
e) 4-(m+5-n)= 4-m-5+n= -1-m+n
f) 4g-(-2h+g-3)= 4g+2h-g+3= 3g+2h+3
Pozdrawiam :)
