Question

3x+4)2−(x−10)2 .

Answer 1

Given:

Expression is

$(3x+4)^2-(x-10)^2$

To find:

The simplified form of the given expression.

Solution:

We have,

$(3x+4)^2-(x-10)^2$

Using $(a+b)^2=a^2+2ab+b^2$ and $(a-b)^2=a^2-2ab+b^2$, we get

$=(3x)^2+2(3x)(4)+(4)^2-[(x)^2-2(x)(10)+(10)^2]$

$=9x^2+24x+16-[x^2-20x+100]$

$=9x^2+24x+16-x^2+20x-100$

On combining like term, we get

$=(9x^2-x^2)+(24x+20x)+(16-100)$

$=8x^2+44x+(-84)$

$=8x^2+44x-84$

Therefore, the correct option is c.