Question

1. Solve the following sums:
(a) Find the value of 34 square-21 square

Answer 1

(34)^2-(21)^2

715 is correct answer

Answer 2

Answer:

Fisrt way :

$34^2 - 21 ^2$ =x

First lets find the  value of $32^2$

$34 ^2 = 32 * 34 = 1156 .. (I)$

Now lets find the value of $21 ^2$

$21 ^2 = 21 *21 = 441...(2)$

Now by putting the value of 1 and 2 in equation we get

$1156 - 441 = 715$

Second method :

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

By using this formula we can solve this problem

so by placing the values in this formula we get :

$= (34^2 - 21^2) \\= (34+21)(34-21)\\=(55)(13)\\= 715.$

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