Răspuns :
a)3-(-7+2)-(-5)+(-3-1+4)-(-7)=
=3-(-5)-(-5)+(-4+4)+7=
=3+5+5+7=
=3+10+7=
=3+17=
=20
b)-7-(3+2-6)-(-1)+(-6+3-1)=
=-7-(5-6)+1+(-9-1)=
=-7-(-1)+1+(-10)=
=-7+1+1-10=
=-7+2-10=
=-5-10=
=-15
=3-(-5)-(-5)+(-4+4)+7=
=3+5+5+7=
=3+10+7=
=3+17=
=20
b)-7-(3+2-6)-(-1)+(-6+3-1)=
=-7-(5-6)+1+(-9-1)=
=-7-(-1)+1+(-10)=
=-7+1+1-10=
=-7+2-10=
=-5-10=
=-15