1.4 * 1 = 15 5 * 4 = 21 4 * 5 = 11 8 * 16 = 48 then: 10 * 9 = () this is the problem of defining new operation

New operations 4 & 1 = 15,5 & 4 = 21,4 & 5 = 11,8 & 16 = 48,10 & 9 =?

4²-1=15
5²-4=21
4²-5=11
8²-16=48
a&b=a²-b
So 10 & 9 = 10 & # 178; - 9 = 91

Why is the value of integral function y = [x] in [- 1,0] equal to - 1?

[x] When x ∈ [- 1,0], the largest integer not greater than x is - 1,
So [x] = - 1

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