Rezolva urmatoarele cerinte: a)afla numarul a,daca ab+ac=520 si b+c=52; b)afla numarul a,daca ab-ac=45 si b-c=9; c)afla suma b+c daca ab+ac+70=170 si a=25; d)afla diferenta b-c,daca ab-ac-48=2 si a=10.

Răspuns :

a) ab+ac=520
a•(b+c)=520
a•52=520
a=10

b)
ab-ac=45
a•(b-c)=45
a•9=45
a=5

c)a•(b+c)=170-70
25•(b+c)=100
b+c=4

d) a•(b-c)=48+2
10•(b-c)=50
b-c=5