​???

We only need to consider the end behavior of 2x^7......this term tends to "outstrip"  the behavior of the other terms as x approaches "large" values

2x^7  will result in a large negative as x tends toward negative infinity....the coefficient is positive and any odd power will make the whole term negative as x approaches infinity

And  2x^7 will tend towards a large positive as x tends toward positive infinity

So....."down and up" describes the end behavior