3 years ago

Factor the expression: X squared + 4x + 21

Mathematics

2 answers:

inessss [21]3 years ago

8 0

This expression can't be factored.

alekssr [168]3 years ago

7 0

(x+3)x+4)
hope this helps

You might be interested in

I need help with this problem.

sdas [7]

Answer:

$\text{4}\quad -3x^{-1}+x^{-2}$

Step-by-step explanation:

The answer choices suggest there is a common factor of (x+2) that can be removed from numerator and denominator.

The denominator factors as ...

$x^3+2x^2=x^2(x+2)$

The numerator obviously has no factors of x. We can try any of several means to determine if (x+2) is a factor. I tried synthetic division and found that the numerator can be written as ...

$-3x^2-5x+2=(-3x+1)(x+2)$

Then the expression simplifies to ...

$\dfrac{-3x^2-5x+2}{x^3+2x^2}=\dfrac{(-3x+1)(x+2)}{x^2(x+2)}\\\\=\dfrac{-3x+1}{x^2}=\dfrac{-3x}{x^2}+\dfrac{1}{x^2}=-3x^{-1}+x^{-2} \qquad\text{matches choice 4}$