How to use permutations and combinations?

Need ! easy 6th grade work! i will put as much points as i can! you so much! i’m learning this in math and it’s soo

Which equation represents a line that is parallel to the line whose equation is 3x-2y=7( show all work)

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.