Hello, ramizashraf!
I don't think you meant what you wrote . . .
You wrote:
\(\displaystyle \text{[ integration sign ] }\underbrace{under\,root\,A\,square} \,+\,\underbrace{\text{under root }x\,square}\; dx\)
. . . . . . . . . . . . . . . . . . . . . . . . . . \(\displaystyle \sqrt{A^2}\) . . . . . . . . . . . . . . . . .\(\displaystyle \sqrt{x^2}\)
And this is just: \(\displaystyle \,\int(A\,+\,x)\,dx\) . . . not very challenging!