题干

对于实数a、b,定义一种运算“⊗”为:a⊗b=a2+ab﹣2,有下列命题:

①1⊗3=2;

②方程x⊗1=0的根为:x1=﹣2,x2=1;

③不等式组 {(2)x4<01x3<0 的解集为:﹣1<x<4;

④点(

1
2
5
2
)在函数y=x⊗(﹣1)的图象上.

其中正确的是(   )

A:①②③④

B:①③

C:①②③

D:③④

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答案(点此获取答案解析)

C

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