/sci/ - Science & Math

>study 1st year math
>equations
>learn different ways of solving them
>do well in the exercises of each method
>reach the end of the chapter
>"here's a final exercise for you"
>"various equations"
>"you decide which method is best"
>get absolutely lost
>don't know where to start

Is there any tricks to find which method is best? Suddenly I feel like I can't solve any equations while before I was doing 10/10 on the exercises..