What is the exact volume of the sphere

What is the anwers for 9+2x=5x-3-x

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.

The table below shows the approximate height of an object x seconds after the object was dropped. the function h(x)= -16x^2 +100 models the data in the table. for which value of x would this model make it the least sense to use? a. -2.75 b. 0.25 c. 1.75 d. 2.25