There are two ways to solve the second problem. The first one is easy to understand, and the general process is as follows: the decomposition term, (x cube -8)+2(x square minus 4).

Then, the first half before the plus sign uses the cubic difference, and the second half after the plus sign uses the square difference. The result is (x-2)(x square +4x+8)=0, obviously x=2.

In the second method, we can use the knowledge of the first derivative to gradually narrow the scope and then find a solution. This method needs to be used flexibly and is not easy to master.

Finally, it is emphasized that there is no need to find a general solution to the high-order equation in high school, and it can generally be solved by decomposition. For objective questions, guessing is ok. The solutions of high school and high order equations are mostly smaller integers. After all, taking the exam is mainly to save time.