Determine if the lines are parallel, perpendicular or neither . 6x+10y=20 and 5x-3y=21 show steps

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.

Due to financial difficulties the owner of 4 skateboard stores is going to close 2 of his stores. based on the money earned at each store, which two stores should remain open?

In 2009, there were 1570 bears in a wildlife refuge. in 2010, the population had increased to approximately 1884 bears. if this trend continues and the bear population is increasing exponentially, how many bears will there be in 2018?