The square root of x is equal to x^1/2.
x to the 1/2 power.
When multiplying 2 numbers with same bases and different exponents, you add the exponents.
x^2 times x^1/2 = x^(2 + 1/2) = x^(5/2)
The answer is A and B, because a square root is basically raising it to the power of 1/2, and when you raise an exponent to another exponent you multiply, and 1/2 times 5 is 5/2.