As dori o mana de ajutor la aceste exercitii

a)
[(-306)•(-3)+87•(-12)]•0=0

b)
-3-10•[362-10•(-24-2•3)]=
=-3-10•[362-10•(-30)]=
=-3-10•(362+300)=
=-3-10•662=
=-3-6620=
=-6623

d)
-1+5•[(-4-2)•(-5)-17]-(18-10)•7=
=-1+5•(-6•-5-17)-8•7=
=-1+5•(30-17)-56=
=-1+5•13-56=
=-1+65-56=
=65-57=
=8

e) {-3•[-7•(15-10-2)-3•(-8)+5]+20-4}•2=
=[-3•(-7•3+24+5)+20-4]•2=
=[-3•(-21+24+5)+20-4]•2=
=(-3•8+20-4)•2=
=(-24+20-4)•2=
=-8•2=
=-16

a)  [ ( - 306 ) × ( - 3) + 87 × ( - 12 ) ] × 0 = 0 
→ aplic proprietatea inmultirii, cand intr-un produs unul din factori este 0 produsul e 0 

[ .....]× 0 = 0

b) - 3 - 10 × [ 362 - 10 × ( - 24 - 2 × 3) ] = - 6 623

= - 3 - 10 × [ 362 - 10 × ( - 24 - 6 ) ]=

= - 3 - 10 × [ 362 - 10 × ( - 30) ] =

= - 3 - 10 × ( 362 + 300 ) = 

= - 3 - 10 × 662 =

= - 3 - 6 620 =

= - 6 623 

d) 

- 1+ 5 × [ ( - 4 - 2 ) × ( - 5 ) - 17 ] - ( 18 - 10 ) × ( + 7) = 8

= - 1 + 5 × [( - 6 ) × ( - 5) - 17 ] -  56 = 

= - 1 + 5 × ( 30 - 17 ) - 56 =

= - 1 + 5 × 13 - 56 =

= - 1 + 65 - 56 =

= 64 - 56 =

= 8

e) 
{ - 3 × [ - 7 × ( 15 - 10 - 2 ) - 3 × ( - 8) + 5 ] + 20  - 4 } × ( + 2) = - 16
= [ - 3 × (- 7 × 3 + 24 + 5 ) + 20 - 4 ] × 2 =
= [ - 3 × ( - 21 + 24 + 5) + 20 - 4 ] × 2 =
= ( - 3 × 8 + 16 ) × 2 =
= ( - 8) × 2 =
= - 16