Question

Rezolva urmatoarele cerinte:a)afla nr.a,daca ab+ac=520 si b+c=52.b)afla nr a ,daca ab-ac=45 si b-c=9.c)afla suma b+c daca ab+ac+70=170si a=25.

Answer 1

a) ab+ac=520
    a(b+c)=520,   dar b+c=52
    a·52=520
    a=520÷52
    a=10
b) ab-ac=45
    a(b-c)=45,    dar b-c =9
    a·9=45
    a=45÷9
    a=5
c)  ab+ac+70=170
     a(b+c)=170-70
     a(b+c)=100,   dar a=25
     25(b+c)=100
     b+c=100÷25
      b+c=4

Answer 2

a(b+c)=520
a×52=520
a=520:52
a=52
b) a(b-c)=45
a×9=45
a=45:9
a=5
c)a(b+c)+70=170
a(b+c)=170-70
a(b+c)=100
b+c=100:a
b+c=100:25
b+c=4