a) 30,5−12=3−12=3−12⋅3+13+1=(3−1)(3+1)2(3+1)=(3)2−122(3+1)=3−12(3+1)=22(3+1)=3+1
b) 3−21,520,5=3−2232=3−232=3−82=3−82⋅3+83+8=(3−8)(3+8)2(3+8)=32−(8)232+16=9−832+4=132+4=32+4
c) 31,5−70,54=323−74=33−74=27−74=27−74⋅27+727+7=(27−7)(27+7)4(27+7)=(27)2−(7)24(27+7)=27−74(27+7)=204(33+7)=533+7
d) (70,5−60,5)0,5(70,5+60,5)0,5=(7−6)0,5(7+6)0,5=(7−67+6)0,5=(7−67+6⋅7+67+6)0,5=[(7−6)(7+6)(7+6)2]0,5=[(7)2−(6)2(7+6)2]0,5=[7−6(7+6)2]0,5=[1(7+6)2]0,5=[(7+6)2]0,5=7+6