Bai 1 tim x,y,z biet
a, \(\frac{x}{1}\)=\(\frac{y}{2}\)=\(\frac{z}{3}\)va 4x-3y+2z=36
b, x:y:z=3:5;(-2) va 5x-y+3z=124
c, 2x=3y,5y=7z va 3x-7y+5z=-30
Bai 2 tim ca so a1,a2,...a9 biet
\(\frac{a1-1}{9}\)=\(\frac{a2-2}{8}\)=\(\frac{a3-3}{7}\)=..........\(\frac{a9-9}{1}\)va a1+a2+........+a9=90
luu y cho cac ban giai bai nay la lien quan den tinh chat cua day ti so bang nhau