Question

Determinati numerele naturale a,b,c stiind ca a+b=90 b+c=110 a+c=100

Answer 1

a+b=90 ; b+c=110 ; a+c=100 ; adunam cele 3 ecuatii

a+b+b+c+a+c=90+110+100 ; 2a+2b+2c=300 I:2 ; a+b+c=150

a=90-b, c=110-b inlocuim a si c in suma celor 3 numere

90-b +b+110-b- =150 ; b=90+110-150 = 200-150 = 50

a=90-50 = 40 ; c = 110-50 = 60