0 × <span>0 = 0
0 </span>× <span>1 = 0
1 </span>× <span>1 = 1
Which means multiplication is closed under {0, 1}
</span><span>1 </span>÷ <span>1 = 1
0 </span>÷ <span>1 = 0
</span>
Division is not closed under {0, 1}
1 + 1 = 2
Addition is not closed under {0, 1}
0 - 1 = -1
Subtraction is not closed under {0, 1} either
So it's only A. Multiplication which is closed under {0, 1}
For any values less than -3, the answer is undefined, because then you have a negative value for √x+3
False, it's the other way around: you divide the numerator by the denominator.
For example, to evaluate 
you divide 8 by 15:
