stiind ca a b+c=21 si a=7 ,calculati axb+axc

Răspuns :

b + c = 21  si   a = 7

a × b + a × c = a × ( b + c ) = 7 × 21 = 147

b+c=21

a=7  

a*b+a*c=?

a*(b+c)=7*21=147