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How would I solve this: Multiply: $(4 + x)(x^2 + 2x +3)$

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    Distribute. Multiply. Add.2011-03-14

2 Answers 2

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This question, as you probably know, requires the use of the distributive property. To use JavaMan's suggestion $(a + b) \cdot c = a \cdot c + b \cdot c$
Let "a + b" be your $4 + x$ and let "c" be your $x^2 + 2x + 3$

Then we need to multiply $a \cdot c$, or $4 \cdot (x^2 + 2x + 3)$, and add it to

$b \cdot c$, which is $x \cdot (x^2 + 2x + 3)$

So $ a\cdot c + b \cdot c = [4\cdot (x^2 + 2x +3)] + [x \cdot (x^2 + 2x + 3)]$ After taking these steps, combine like terms and write the result in order of decreasing exponents (for convention's sake)

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First, distribute the 4. Add the products of 4 and $x^2$, 4 and 2x, 3 and 4.

Then, distribute the x. Add the products of x and $x^2$, x and 2x, 3 and x.

Then all you have to do is add all of the items you have left.

After the distributions, you should have

$4x^2 + 8x + 12 + x^3 + x^2 + 3x =$

$x^3 + 5x^2 +11x + 12$

(Yay cool text!)

  • 4
    just put dollar sig$n$s around the parts you want to cool-ify.2011-03-14