Question

Thu gọn biểu thức : (3a-1)^2+2(9a^2-1)+(3a+1)^2

Answer 1

\(\left(3a-1\right)^2\) + \(2\left(9a^2-1\right)\) + \(\left(3a-1\right)^2\)
= \(\left(3a-1\right)^2\) + \(2\left(3a-1\right)\left(3a+1\right)\) + \(\left(3a-1\right)^2\)
= \(\left(3a-1+3a+1\right)^2\)
= \(\left(6a\right)^2\)
= \(36a^2\)  

Answer 2

\(\left(3a-1\right)^2+2\left(9a^2-1\right)+\left(3a+1\right)^2\)

\(=\left(3a-1+3a+1\right)^2\)

\(=36a^2\)