①下列计算正确的是()A(-3x)^2=-9x^2B.(-3x)^2=9x^2C.(-3)^2=-6x^2D(-3x)^2=6x^2
②计算a(-2a)^3·(a^2)^5的结果是()(要化简)
③如果(x^3y^n)^2=x^6y^8,则n等于().
④已知2^x=a.2^y=b.求(2^x+y)+(2^3x+2y)的值
⑤已知x^n=2.y^n=3,求(x^2y)^2n的值