x=-3,y的绝对值=5,z+3=0,求xy-yz+xz的值

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x=-3,y的绝对值=5,z+3=0,求xy-yz+xz的值

y的绝对值=5,z+3=0所以y=5或y=-5,z=-3
当y=5时,xy-yz+xz=(-3)x5-5x(-3)+(-3)x(-3)=9
当y=-5时,xy-yz+xz=(-3)x(-5)-(-5)x(-3)+(-3)x(-3)=9

x=z=-3
所以 xy-yz+xz
=xy-yx+xz
=xz
=(-3)*(-3)
=9

9

x=-3,
y的绝对值=5, 则y=±5
z+3=0, 则z=-3
(1) y=5时
xy-yz+xz=(-3)*5-5*(-3)+(-3)*(-3)
=-15+15+9
=9
(2) y=-5时
xy-yz+xz=(-3)*(-5)-(-5)*(-3)+(-3)*(-3)
=15-15+9
=9
综上:xy-yz+xz=9