I need help with an equation... I can't understand it I've tried it a couple of times and I still get it wrong...so help plz?

Answer:
(f·g)(x) = x³ -8x² +20x -16
Step-by-step explanation:
The distributive property is useful for this.
(f·g)(x) = f(x)·g(x) = (x² -6x +8)(x -2)
= x(x² -6x +8) -2(x² -6x +8)
= x³ -6x² +8x -2x² +12x -16
(f·g)(x) = x³ -8x² +20x -16
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Additional comment
I find it convenient to separate the terms of the shortest polynomial. That way, the distributive property doesn't need to be used quite so many times. Of course, any outside minus sign applies to all terms inside parentheses.