①2⊗5=22−2×2×5=−16,故①正确;
②32⊗(−1)=322−2×2×(−1)=30=0是有理数,故②错误;
③方程x⊗y=0得x2−2xy=0是二元二次方程,故③正确:
④不等式组{(−3)⊗x+1>02⊗x−5>0等价于{(−3)2−2×(−3)x+1>022−2×2x−5>0,
解得−35<x<−41,故④正确;
故答案为:①③④.
①2⊗5=22−2×2×5=−16,故①正确;
②32⊗(−1)=322−2×2×(−1)=30=0是有理数,故②错误;
③方程x⊗y=0得x2−2xy=0是二元二次方程,故③正确:
④不等式组{(−3)⊗x+1>02⊗x−5>0等价于{(−3)2−2×(−3)x+1>022−2×2x−5>0,
解得−35<x<−41,故④正确;
故答案为:①③④.