Question

Va rog sa ma ajutati!
a) daca a=7,b+c=15 si b-c=7,calculati ab+ac si ab-ac
b) daca a=7 si b+c+d=70,calculati ab+ad
c) daca a=3 si b+c+d=30,calculati 3a+2(ab+ac+ad)

Answer 1

1. ab+ac=a(b+c)=7*15=105 si ab-ac=a(b-c)=7*7=49
2. ab+ac+ad=a(b+c+d)=7*70=490
3. 3a+2(ab+ac+ad)=9+2a(b+c+d)=9+6*30=9+180=189