Evaluate each of the following using identities:$(399)^2$

Given:

$(399)^2$

To do:

We have to evaluate the given expression using a suitable identity.

Solution:

We know that,

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

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

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

Therefore,

$(399)^{2}=(400-1)^{2}$

$=(400)^{2}-2 \times 400 \times 1+(1)^{2}$

$=160000-800+1$

$=160001-800$

$=159201$

Hence, $(399)^{2}=159201$.

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Updated on: 10-Oct-2022

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