Question

Se stie ca a+b+c=7 . Calculati : 
A) 2a+2b+2c=
B) 10a+10b+10c=
C) a x 13 + b  x 13 + c x 13 + 21 =
Am pus x in loc de ori  

Answer 1

A) 2a+2b+2c=
2(a+b+c)=
=2x7=14

B) 10a+10b+10c==
10(a+b+c)=
=10x7=70

C) a x 13 + b  x 13 + c x 13 + 21 =
13(a+b+c)+21=
13x7+21=
=91+21
=112