How do I find a factor of x^3 - 3x^2 - 28x?
first notice the common factor of x
x^3 - 3x^2 - 28x
= x(x^2 - 3x - 28)
now do the quadratic
= x(x-7)(x+4)
(notice (-7)(+4) = -28 and -7+4 = -3 )
So x - 7 is a factor?
Didn't I just show you that it was ?
Did you not look at my answer ?
Yes, I saw your answer. I was just confirming :).
To find a factor of the expression x^3 - 3x^2 - 28x, we can use a method called factoring. Here's a step-by-step guide on how to find a factor:
Step 1: Look for a common factor
Check if there is a common factor among all the terms of the expression. In this case, the common factor is x, so we can factor out an x:
x(x^2 - 3x - 28)
Step 2: Factor the quadratic expression
Now we have the quadratic expression x^2 - 3x - 28. We need to factor this further. To do that, we look for two numbers that multiply to -28 and add up to -3. In this case, the numbers are -7 and 4, because -7 * 4 = -28 and -7 + 4 = -3.
So, the quadratic expression can be factored as:
x(x - 7)(x + 4)
Therefore, the factor of x^3 - 3x^2 - 28x is x(x - 7)(x + 4).