m²-mn-3m+3n=0,5²-0,5*0,25-3*0,5+3*0,25=0,25-0,125-1,5+0,75=1-1,625=-0,625
a²-ab-2a+2b=(7/20)²-7/20*0,15-2*7/20+2*0,15=49/400-7/20*3/20-14/20+2*3/20= 49/400-21/400-14/20+6/20=28/400-280/400+120/400=132/400=33/100=0,33
m²-mn-3m+3n=0,5²-0,5*0,25-3*0,5+3*0,25=0,25-0,125-1,5+0,75=1-1,625=-0,625
a²-ab-2a+2b=(7/20)²-7/20*0,15-2*7/20+2*0,15=49/400-7/20*3/20-14/20+2*3/20= 49/400-21/400-14/20+6/20=28/400-280/400+120/400=132/400=33/100=0,33