Question

1.Calculati
a)1/3×7+4/3×21/28+3 1/2×7 3/5
b)(65/195+108/324+122/366)×(24/168-6/42
c)(3 4/1+1 2/7-1 17/28)×1 15/41
d)28/31×[1/4+(2 1/2-7/4):7/8]

2.
a)[1\3+1/3:(1-1/3)]:3/2
b)28/31×[1/4+(2 2/1-7/4):7/8]

VA ROG FRUMOS !!!

Answer 1

a)1/3×7+4/3×21/28+3 1/2×7 3/5=
=7/3+1+7/2×38/5=
=7/3+1+7×19/5=
=(35+15+399)/15=
=449/15

b)(65/195+108/324+122/366)×(24/168-6/42)=
=(1/3+1/3+1/3)×(1/7-1/7)=1×0=0

c)(3 4/1+1 2/7-1 17/28)×1 15/41=           
=(12+9/7-35/28)×56/41=
=(12+9/7-5/4)×56/41=
=(12*28+9*4-5*7)×56/41=
=(336+36-35)×56/41=
=337×56/41=
=18872/41  ( cred ca numitorul  primei fractii nu e 1)

d)28/31×[1/4+(2 1/2-7/4):7/8] =
=28/31×[1/4+(5/2-7/4) ×8/7] =
=28/31×[1/4+(10-7)/4 ×8/7] =
=28/31×[1/4+3/4 ×8/7] =
=28/31×[1/4+6/7] =
=28/31×(7+6*4)/28 =
=28/31×31/28 =1

a)[1/3+1/3:(1-1/3)]:3/2=
=(1/3+1/3:2/3) ×2/3=
=(1/3+1/3×3/2) ×2/3=
=(1/3+1/2) ×2/3=
=(2+3)/6 ×2/3=
=5/9


b)28/31×[1/4+(2 2/1-7/4):7/8]=
=28/31×[1/4+(5/2-7/4) ×8/7] =
=28/31×[1/4+(10-7)/4 ×8/7] =
=28/31×[1/4+3/4 ×8/7] =
=28/31×[1/4+6/7] =
=28/31×(7+6*4)/28 =
=28/31×31/28 =1