Question

what is 21 multiplied by 21

Answer 1

Answer:

21*21 =441 is the correct

Answer 2

Question:

what is $21\times21$

Given:

$21\times21$

To Find:

$21\times21$

Identity Used:

$(a+b)^2=a^2+b^2+2ab$

Solution:

$21\times21$

$21\times21\\\\\\21^2\\\\\\(20+1)^2\\\\\\(a+b)^2=a^2+b^2+2ab\\\\\\a = 20\\\\\\b=1\\\\\\20^2+1^2+2\times20\times1\\\\\\400+1+2\times20\\\\\\400+1\+40\\\\\\440+1\\\\\\44121^2=441$

Answer:

21² = 441