Answer:

Step-by-step explanation:
Write the polynomials one above the other to multiply them:


<h3 /><h3>First Step</h3>
Multiply each element of
by 4:
The result is:
[1]
As it can be seen, only the coefficients are multiplied by 4, and when the operation involves multiplication with coefficients with different operators (+ or -), the following rules are crucial:




That is why 4 times -5 = -20, 4 times 1 = 4, and so 4 times 3 = 12.
<h3 /><h3>Second Step</h3>
Multiply each element of
by x:
The same rules apply here, but including the addition of powers or exponents.
The result is:
[2].
or 


<h3 /><h3>Third Step</h3>
Sum all similar terms of the previous results [1] and [2].
The result is:
, because


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