in paranteza rotunda aduc la acelasi numitor care este 42
(8×2/42-3×6/42+5×3/42-25/42)×(-5×4+1/4)+[-0,8(3)]=
=(16/42-18/42+15/42-25/42)×(-19/4)+(-83-8/90)=
=(-12/42)×(-19/4)+(-91/90)=
(-12/42 o simplific cu 2=-6/21
= -6/21×(-19/4)-91/90=
= 114/84-91/90=
numitor comun 1260
=15×114/1260-14×91/1260=
=1710-1274/1260=436/1260 se simplifica cu 2=218/630 se simplifica cu 2=109/315
