{x,y,z}->ip {3,4,5}
3x=4y=5z=k =>
x=k/3
y=k/4
z=k/5
k/3*k/4+k/3*k/5+k/4*k/5=20
k^2/12+k^2/15+k^2/20=20 -aducem la numitor comun ,60 in acest caz
5k^2+4k^2+3k^2/60=1200/60 -înmulțim cu 60
12k^2=1200 /:12
k^2=100 => k=10
x=k/3
x=10/3
x=3,(3)
y=k/4
y=10/4
y=2,5
z=k/5
z=10/5
z=2
