Question

Answer 1

Bài 2:

Đặt $\frac{x-1}{5}=\frac{y-2}{3}=\frac{z-1}{4}=t$

$\Rightarrow x=5t+1; y=3t+2; z=4t+1$

Khi đó:

$2x-3y-2z=-27$

$\Rightarrow 2(5t+1)-3(3t+2)-2(4t+1)=-27$

$\Rightarrow -7t-6=-27$

$\Rightarrow -7t=-21$

$\Rightarrow t=3$

$x=5t+1=16; y=3t+2=11; z=4.3+1=13$

Answer 2

Bài 1.

 Đặt $6x=10y=15z=t$

$\Rightarrow x=\frac{t}{6}; y=\frac{t}{10}; z=\frac{t}{15}$

$x+y-z=\frac{t}{6}+\frac{t}{10}-\frac{t}{15}=90$

$\Rightarrow t(\frac{1}{6}+\frac{1}{10}-\frac{1}{15})=90$

$\Rightarrow t.\frac{1}{5}=90$

$t=90.5=450$

$x=t:6=75; y=t:10=45; z=t:15=30$