Sound is used to measure ocean depth. sound travels 1.5 km per second through water. if it takes 3.7 seconds for a sound to reach the bottom of the ocean, how deep is the ocean

What does x = in this equation x+3+2x=x+5

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.

Which expression demonstrates the use of the commutative property of addition in the first step of simplifying the expression (-1+i)+(21+5i)+0