This is regarding problem 1.11 step 3 and 4 in the molecular quantum mechanics book.
in step 3, how come the [v(x),x] part goes to 0? because they communte? how do we know this? in step 4, how do we get from the first line to the second?

The triangles are similar. what is the value of x? show your work.

20 points for the brainliest? drag each tile to the correct box. not all tiles will be used. arrange the steps to solve the equation . plz

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.