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设=(1,-2),=(-3,4),=(3,2)则(+2)·=
A.(-15,12)
B.0
C.-3
D.-11
设=(1,-2),=(-3,4),c=(3,2),则(+2)·=
设a=(1,-2),b=(-3,4),c=(3,2),则(a+2b)·c=
A.(-15,12) B.0 C.-3 D.-11