Question

a) Daca b+c=15 si a= -20 , calculati ab+ac ;
b) Daca b-c=23 si a = -11 ,calculati ab-ac.

Answer 1

a)ab+ac= a( b+c)     b) ab-ac=a(b-c)
-20 ori 15= -300           -11 ori 23=-253.

Answer 2

a. b+c=15; a=-20
⇒-20[b+c]=[-20]·15=-300;
b. b-c=23; a=-11;
⇒-11[b-c]=[-11]·23=-253;