Câu trả lời:
TQ: \(^{\sqrt{a^2+a^2\left(a+1\right)^2+\left(a+1\right)^2}}=\left(a+1\right)^2-a.\)
Thật vậy ta có: \(a^2+a^2\left(a+1\right)^2+\left(a+1\right)^2=a^4+2a^3+3a^2+2a+1\)
\(\left(\left(a+1\right)^2-a\right)^2=\left(a^2+a+1\right)^2=a^4+2a^3+3a^2+2a+1\)