[Math] General formula for multiplying two degree-two polynomials together

polynomials

I am trying to figure out a general formula for getting the product of two degree-2 polynomials.

For example, I have $ax^2+bx+c$ and want to multiply it by $dx^2+ex+f$ where all variables are constants except for $x$. What would be the product of these two polynomials?

I tried computing the general formula, but I don't believe I got the correct answer.
Thanks for your help!

What I got was $adx^4 + (ae+bd)x^3 + (af+be+cd)x^2 + (ce+bf)x + cf$.

Best Answer

$$(a_{_2}x^2+a_{_1}x+a_{_0})\cdot(b_{_2}x^2+b_{_1}x+b_{_0})=\sum_{k=0}^4\sum a_i\cdot b_{k-i}\cdot x^k$$

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