A.a+1b.a2+1C. Root number a+ 1 D. Root number A+1
Analysis: the arithmetic square root of this number is a, so this natural number is a? The next natural number next to this natural number is a? + 1
2. It must be a root sign (20-a), otherwise it cannot be an integer. A < 20 (because 20-a >；; 0), the maximum value is the arithmetic square root of the largest complete square integer within 20, that is, the root number 16=4, so the root number (20-a)=4, and a=20- 16=4.
3. Landlord, I typed an extra radical symbol,,,, I think it should be the radical symbol 12x. If there are two radicals, it is too difficult to calculate ... radical number 12x=2 times (radical number 3x), and the minimum value is the smallest complete square positive integer divisible by 3, that is, 9, so x=3 is.