Question

Buna, ma puteti ajuta la urmatoarele exercitii? Multumesc!
1. {[(27/25-1/2•21/25)]•25/3 - 1} • 3013-10^3=

2. ( 65/195+ 108/324+122/366)•(24/168-6/42)=

3. Calculati:
A) a•b+a•c stiind ca a=3/16 si b+c= 4/9
B) 9a+4b+5c stiind ca a+b= 10/3 si ca a+c=5

Dau coroana!!! Va roog!! Multumesc

Answer 1

1. {[(27/25-1/2•21/25)]•25/3 - 1} • 3013-10³=
= [(9-1/2 • 7) - 1] • 3013-10³=
= [(9-7/2-1] • 3013-10³=
= (18-7-2)/2 • 3013-10³=
=  9/2 • 3013-10³=
=27117/2 -1000 =
=(27117-2000)/2=25117/2=12558,5

2. ( 65/195+ 108/324+122/366)•(24/168-6/42)=
=( 1/3+ 1/3+1/3)•(1/7-1/7)=
=1•0=0

3. Calculati:
A) a•b+a•c stiind ca a=3/16 si b+c= 4/9=
a•b+a•c=a•(b+c)=3/16•4/9=1/12

B) 9a+4b+5c stiind ca a+b= 10/3 si ca a+c=5
9a+4b+5c=4a+4b+5a+5c=4(a+b)+5(a+c)=
=4×10/3+5×5=40/3+25=115/3=38,(3)