Hi, recently I was given a question by a teacher:

Simplify: $\displaystyle \frac{2a^4 +a^3 + 4a^2 + a + 2}{4a^4 + 4a^3 + a^2 - 4}$

After the whole class struggled over the week, our teacher revealed the answer: $\displaystyle \frac{a^2 + 1}{2a^2 + a - 2}$

How do I get to this answer??

Please help, thanks BG