Question

tìm x,y,z

a) 4x=5y và 3x-2y=35

b) \(\frac{x}{2}=\frac{y}{3}=\frac{z}{5}\)và x+y+z= -90

c) x:y:z=3:5:(-2) và 5x-y+3z=124

d) \(\frac{x-4}{3}=\frac{y-6}{3}=\frac{z-8}{4}\)và x+y+z=27

e) \(\frac{x}{1}=\frac{y}{2}=\frac{z}{3}\)và 4x-3y+2z=36 Giúp mk vs mk đang cần gấp, trc 20h tối nay nhé , mk sẽ tik thật nhiều

Answer 1

b) \(\dfrac{x}{2}=\dfrac{y}{3}=\dfrac{z}{5}\) = \(\dfrac{x+y+z}{2+3+5}=\dfrac{-90}{10}=-9\)

\(\dfrac{x}{2}=-9\) => x= -18

\(\dfrac{y}{3}=-9\) => y = -27

\(\dfrac{z}{5}=-9\) => z = -45

Answer 2

a) \(4x=5y\) <=> \(x=\dfrac{5y}{4}\)

\(3\cdot\dfrac{5y}{4}-2y=35\)

=> y = 20

=> x = \(\dfrac{5\cdot20}{4}\)=25

Answer 3

ten nghe quen vler==

Answer 4

d) \(\dfrac{x-4}{3}=\dfrac{y-6}{3}=\dfrac{z-8}{4}=\dfrac{x-4+y-6+z-8}{3+3+4}=\dfrac{x+y+z-18}{10}=\dfrac{27-18}{10}=\dfrac{9}{10}\)

\(\dfrac{x-4}{3}=\dfrac{9}{10}\) => x=\(\dfrac{67}{10}\) = 6,7

\(\dfrac{y-6}{3}=\dfrac{9}{10}\) => y= \(\dfrac{87}{10}=8,7\)

\(\dfrac{z-8}{4}=\dfrac{9}{10}\) => z= \(\dfrac{58}{5}=11,6\)