Answer:
3x^3+ 12x^2-15x
Step-by-step explanation:
First, you would have to distribute the 3x to everything in the parentheses. So you can write it out as (3x*x^2)+(3x*4x)+(3x*5). Solving this will give you the answer. We'll start off with (3x*x^2). Because we are MULTIPLYING, this part will equal to 3x^3. There is ONE x with 3x (think of it as 3x^1) and 2 x's in x^2, having a total of 3 x's, or x^3. Since the 3 is being multiplied as well, we can write it as 3x^3.
Second, we will solve (3x*4x). We are multiplying, so first we multiply 3*4 and then x*x. 3*4 is 12 and x*x is x^2. There are 2 x's being mutipled by each other, so the x becomes squared. Now we finish and multiply 12*x^2 wich is 12x^2.
Lastly, we solve (3x*5). 3x is being multiplied 5 times which gives us 15x.
I hope this helped :)
+2r-2n+7