Stan and Ollie work on the integral

${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}2x(x^2+2)dx$

Stan lets $u=x^2+2$ and proceeds to get

${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}$udu$=\frac{u^2}{2}+C=\frac{(x^2+2{)}^2}{2}+C$

Ollie multiplies out the function under the integral and gets

${\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}(2x^3+4x)dx=\frac{x^4}{2}+2x^2+C$

How can they both be right?