Question

Numerele x,y si z sunt direct propoortionale cu 3, 7 respectiv 2 si xy+yz =175 .aflati cele 3 numere.

Answer 1

{x,y,z}dp{3,7,2}
x/3=y/7=z/2=k
x=3k
y=7k
z=2k
xy+yz=175
3k·7k+7k·2k=175
21k²+14k²=175
35k²=175
k²=175/35
k²=5
k=√5
x=3√5
y=7√5
z=2√5

verificare
xy+yz=175
3√5x7√5+7√5x2√5=175
105+70=175