sequences and series - Proving a relation between $sumfrac{1}{(2n-1)^2}$ and $sum frac{1}{n^2}$

I ran into this question:

Prove that:

$$\sum_{n=1}^{\infty}\frac{1}{(2n-1)^2}=\frac{3}{4}\sum_{n=1}^{\infty}\frac{1}{n^2}$$

Thank you very much in advance.