x/y=3/7
=>x/3=y/7=(x-y)/(3-7)=20/-4=-5
=>x=-5.3=-15
y=-5.7=-35
\(\frac{x}{y}=\frac{3}{7}\Rightarrow7x=3y\Rightarrow\frac{x}{3}=\frac{y}{7}=\frac{x-y}{3-7}=\frac{20}{-4}=-5\)
=>x=-15;y=-35
vậy x=-15;y=-35
tim x,y,z khi
\(\frac{x}{7}=\frac{y}{3}va\)x-24=y
\(\frac{x}{5}=\frac{y}{7}=\frac{z}{2}\)va y-x=48
\(\frac{x}{2}=\frac{y}{3};\frac{y}{4}=\frac{z}{5}\)va x-y- z=28
\(\frac{x}{3}=\frac{y}{5}=\frac{z}{7}\)va 2x+3-z=-14
Tim x,y,z biet
a,5x= 8y= 20z va x-y-z = 3
b,\(\frac{6}{11}x=\frac{9}{2}y=\frac{18}{5}z\)va -x+y+z =120
c,\(\frac{x}{12}=\frac{y}{9}=\frac{z}{5}\)va x . y . z =20
d,\(\frac{x}{5}=\frac{y}{7}=\frac{z}{3}\)va \(^{x^2+y^2-z^2}\)=585
C, CHO 7X=3Y VA X -Y =16
D, CHO \(\frac{X}{2}=\frac{Y}{3}=\frac{Z}{4}\)VA A +2B -3C = -20
E, CHO X :Y :Z =7:4:2 VA X- 3Z =9
F,CHO \(\frac{X}{Y}=\frac{7}{10};\frac{Y}{Z}=\frac{10}{3}\)VA X+Y+Z=120
G,CHO 3X=4Y=5Z VA X-Y-Z=-42
Tim cac so x,y,z biet \(\frac{x}{5}=\frac{y}{7}=\frac{z}{3}\)va x2 va y2 va z2
A, CHO \(\frac{X}{4}=\frac{Y}{7}\)VA X .Y=112, TIM X,Y
B, CHO \(\frac{X}{2}=\frac{Y}{5}\)VA X+Y= -21
Tim x,y,z :
a) x=y:2,\(\frac{y}{4}=\frac{z}{5}\)va 2x+2y-z-7=0
b)\(\frac{1}{2}x=\frac{2}{3}y=\frac{3}{4}z\)va x-y=15
c)\(\frac{x}{y}=\frac{2}{3}\), \(\frac{x}{z}=\frac{1}{2}\)va \(x^3\)- xyz=-16
Tim x, y:
\(\frac{x}{3}=\frac{y}{7}\) va\(y^2-x^2=160\)
TIM X, Y ,Z , BIET :\(\frac{x-2}{6}=\frac{y+3}{9}=\frac{z-7}{10}\)va \(x+y+z=106\)
tim x va y:
\(\frac{x+3}{y+5}=\frac{x+5}{y+7}\)
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