1.-(7-3)-(5-2)-[(12-6)-(9-5)] =
-4-3-[6-4] =
-7-2 =
-9
2.-[-5+7*(-3)]+21/7-4 =
-[-5-21]+3-4 =
+26-1=
+25
3.18/(6*2-3)-[16-(-4)*2] =
18/12-3-[16+8]=
18/9-8=
9-8=
1
4.-[5/(-5)+2/(-2)]-10/(3*5-5) =
-[-1-1]-10/(15-5)=
1+1-10/10=
2-1=
1
5.3*[2,1-(3,5-2,7)]+2/0,5=
3*[2,1-0,8]+2/0,5=
3*[1,3]+4=
3,9+4=
7,9
6.[(5,3-0,4)*(5,71-3,4)]/4,5+3,7 =
[4,9*2,31]/4,5+3,5=
11,319/4,5+3,5=
2,51533...+3,5=
6,01533...
Espero que lo entiendas y que te sirva, suerte!