x=-3,y的絕對值=5,z+3=0,求xy-yz+xz的值

x=-3,y的絕對值=5,z+3=0,求xy-yz+xz的值

y的絕對值=5,z+3=0所以y=5或y=-5,z=-3
當y=5時,xy-yz+xz=(-3)x5-5x(-3)+(-3)x(-3)=9
當y=-5時,xy-yz+xz=(-3)x(-5)-(-5)x(-3)+(-3)x(-3)=9