Answer:
21
Step-by-step explanation:
√(35x)
The prime factorization of 35 is 5×7. To simplify the radical, the expression underneath must be a multiple of a perfect square. So we need to choose a value of x that has either 5 or 7 as a factor.
21 has a factor of 7. Let's see:
√(35×21)
√(5×7×3×7)
√(15×7²)
7√15
