Răspuns :
x+y+z=90
x=(y+z)/2
z=1/3 *y
z=y/3
x=(y+y/3)/2 aducem la acelasi numitor in paranteza
x=(3y+y)/3/2
x=4y/3/2
x=4y/3 *1/2
x=2y/3
2y/3 +y +y/3=90 aducem la acelasi numitor
2y+3y+y=180
6y=180
y=30
x=30/3=10
x=2*30/3= 2*10=20
x=(y+z)/2
z=1/3 *y
z=y/3
x=(y+y/3)/2 aducem la acelasi numitor in paranteza
x=(3y+y)/3/2
x=4y/3/2
x=4y/3 *1/2
x=2y/3
2y/3 +y +y/3=90 aducem la acelasi numitor
2y+3y+y=180
6y=180
y=30
x=30/3=10
x=2*30/3= 2*10=20