Tính
\(1.\left(x+2y\right)^2\) \(5.\left(\frac{x}{2}-2y\right)\)
\(2.\left(2x+3y\right)^2\) \(6.\left(\sqrt{2x-y}\right)^4\)
\(3.\left(x+\frac{1}{3}\right)^4\) \(7.\left(x+1\right)\left(x^2-x+1\right)\)
\(4.\left(2x+y^2\right)^3\) \(8.\left(x-3\right)\left(x^2+3x+9\right)\)