Question

fie numerele naturale a,b,c,d. a) daca a*b=2/15 si a*c=11/15 ,calculati a*(b+c)
b)daca a*c=7/36 si b*c=19/48, calculati c*(b-a)
c)daca a=5/6 , b+c=7/20 si c-d =1/24, calculati a*b+2*a*c-a*d

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MULTUMESC :)

Answer 1

a) ab=2/15
ac=11/15
a(b+c)=ab+ac=2/15+11/15=13/15

b)c(b-a)=bc-ac=19/48-7/36=(3·19-4·7)/144=(57-28)/144=29/144

c)ab+2ac-ad=a(b+2c-d)=a(b+c+c-d)=5/6(7/20+1/24)=5/6[(6·7+1·5)/120]=
5/6[(42+5)/120]=5/6·47/120=1/6·47/24=47/144

Answer 2

a)a*(b+c)=a*b+a*c=

2/15+11/15=
13/15
b)c*(b-a)=c*b-c*a=
19/48-7/36=57/144-28/144=
29/144
c)a*b+2*a*c-a*d=
a*(b+c)+a*(c-d)=
5/6*7/20+5/6*1/24=
100/42+120/6=
100/42+840/42=
940/42