若y-x+z=-4,x方-(y+z)方=8,则x+y+z=?

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若y-x+z=-4,x方-(y+z)方=8,则x+y+z=?

若y-x+z=-4,x方-(y+z)方=8,则x+y+z=?
若y-x+z=-4,x方-(y+z)方=8,则x+y+z=?

若y-x+z=-4,x方-(y+z)方=8,则x+y+z=?
因为x方-(y+z)方=8.
所以[x-(y+z)][x+(y+z)]=8
(x-y-z)(x+y+z)=8
-(y-x+z)(x+y+z)=8
又因为y-x+z=-4
所以x+y+z=8/-(-4)=2

y-x+z=-4,x²-(y+z)²=[x-(y+z)]*[x+(y+z)]=4×[x+(y+z)]=8得x+y+z=2

(Y+Z)=X-4
X^2-(Y+Z)^2=8
解得x=3
y+z=-1
x+y+z=2

x方-(y+z)方=(x+y+z)(x-y-z)=-(x+y+z)(y-x+z)
8=4(x+y+z)
x+y+z=2