Prove That $\frac { x ^ { 3 } + 7 x ^ { 2 } + 3 } { 2 x + 1 }$

Prove that $\frac { x ^ { 3 } + 7 x ^ { 2 } + 3 } { 2 x + 1 }$ is $\Theta \left( x ^ { 2 } \right)$ .