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a) A = x - y + z + z + y + x - 2y
A = (x + x) + (-y + y) + (z + z) - 2y
A = 2x + 0 + 2z - 2y
A = 2 .(x + z - y)
b) Thay x = 3 ; y = -1 ; z = 2 vào biểu thức A , ta được :
A = 2 .[3 + 2 - (-1)]
A = 12
Vậy A = 12
Chúc bạn học tốt !
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2x + y + 3z - ( x - y + z )
= 2x + y + 3z - x + y - z
= x + 2y + 2z
\(\left(2x+y+3z\right)-\left(x-y+z\right)\)
\(=2x+y+3z-x+y-z\)
\(=x+2y+2z\)
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1/\(\left(x-y-z\right)-\left(2x+y+z\right)+\)\(\left(2z-2y\right)=x-y-z-2x-y-z+2z-2y\)
\(\left(x-2x\right)+\left(-y-y-2y\right)+\left(-z-z+2z\right)=-x-4y\)
2/\(\left(m-n-p\right)-\left(-m+n-p\right)-\left(n+m\right)=m-n-p+m-n+p-n-m\)
\(=\left(m+m-m\right)+\left(-n-n-n\right)+\left(-p+p\right)=-m-3n\)
3/\(\left(2a+b+c\right)-\left(b+2a+c\right)-\left(2c+b\right)=2a+b+c-b-2a-c-2c-b\)
\(=\left(2a-2a\right)+\left(b-b-b\right)+\left(c-c-2c\right)=-b-2c\)
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giải luôn nhé
A= -2x+4y-6z+3x+6y-6-3z
=x+10y-9z-6
B=4x-6y+8z-4x+12y-4z-5z+5x
=5x+6y-z
chúc bạn hk giỏi!!!
A = \(-2\left(x-2y+3z\right)-3\left(-x-2y+2\right)-3z\)
A = \(-2x+4y-6z+3x+6y-6-3z\)
A = \(\left(-2x+3x\right)+\left(4y+6y\right)-\left(6z-3z\right)-6\)
A = \(-x+10y-2z-6\)
B = \(2\left(2x-3y+4z\right)-4\left(x-3y+z\right)-5\left(z-x\right)\)
B = \(4x-6y+8z-4x+12y-4z-5z+5x\)
B = \(\left(4x-4x+5x\right)-\left(6y+12y\right)+\left(8z-4z-5z\right)\)
B = \(5x-18y-1z\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(A=-\left(x+y-z\right)+\left(x-z\right)+\left(y-9\right)\)
\(A=-x-y+z+x-z+y-9\)
\(A=-9\)
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(2x-y+z)+(y-z+x)+(z-2x+y)
= 2x - y + z + y - z + x + z - 2x + y
= (2x - 2x + x) + (y - y + y) + ( z - z + z)
= x + y + z
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=3x-3y+y-2x+z-x-2y+z
=(3x-2x-x)-(3y-y+2y)+(z+z)
=0-4y+2z
=2z-4y
giải hết ra lun và đáp số bằng mấy