Question

√21×√21 is
1)21
2)√21
3)√42
4)42​

Answer 1

Answer:

√21×√21= 21

For example : √2×√2= 2

In this √2 is a positive algebraic number, when it is multiplied by itself, it gives the number 2

Answer 2

$\sqrt{21} \times \sqrt{21} = 21$

When two same under roots are multiplied then the under root is removed...