Question

Tính giá trị của A=x+2y+3z

biết (x+2y)²+(y-1)²+(x-z)²=0

giúp mik vs nha 

Answer 1

vì \(\left(x+2y\right)^2+\left(y-1\right)^2+\left(x-z\right)^2=0\Leftrightarrow\)

       \(\left(x+2y\right)^2=0\Leftrightarrow x+2y=0\Leftrightarrow x=2y\left(1\right)\)

       \(\left(y-1\right)^2=0\Leftrightarrow y-1=0\Leftrightarrow y=1\left(2\right)\)

          \(\left(x-z\right)^2=0\Leftrightarrow x-z=0\Leftrightarrow x=z\left(3\right)\)

 \(\left(1\right)\left(2\right)\left(3\right)\Rightarrow2y=x=y=2\left(4\right)\)

                      \(\left(4\right)\Leftrightarrow A=2+2+3\times2=10\)