Question

1. Efectuati:
a) 2,4+1 /9•[-7/10+2•(-3/11+1/2)]=
b) -3/41•20 1/2-8/3•(1-5/13:2/13)=
c) (-9/13)•[-0,(39)]•(20/21)
d) -4/5•(-3/16+1/8)+3/10/•(1-1/2)

Answer 1

a) 2,4+1 /9*[-7/10+2*(-3/11+1/2)]=24/10+1 /9*[-7/10+2*(-6/22+11/22)]=
=24/10+1 /9*(-7/10+2*5/22)=24/10+1 /9*(-7/10+5/11)=
=24/10+1 /9*(-77/110+50/110)=24/10+1 /9*  -27/110=24/10 -3/110=
=264/110-3/110=261/110


b) -3/41*20 1/2-8/3*(1-5/13:2/13)= -3/41*20 1/2-8/3*(1-5/2)= -3/41*20 1/2-8/3*(-3/2)=-3/41*20 1/2+4


c) (-9/13)*[-0,(39)]•(20/21)= -9/13*(-39/99)*(20/21)= -9/13*(-13/33)*20/21=
=3/11*20/21= 20/77


d) -4/5*(-3/16+1/8)+3/10*(1-1/2)= -4/5*(-3/16+2/16)+3/10*(2/2-1/2) =
= -4/5*(-1/16)+3/10*1/2= 1/20+3/20=1/20+3/20=4/20=1/5