Question

what is the factored form of $x^2 - 4x - 5$?
\bigcirc \\ (x + 5)(x - 1)
\bigcirc \\ (x + 5)(x + 1)
\bigcirc \\ (x - 5)(x - 1)
\bigcirc \\ (x - 5)(x + 1)

Explanation:

Step1: Recall factoring quadratic

We need two numbers that multiply to -5 (the constant term) and add to -4 (the coefficient of x).

Step2: Find the numbers

The numbers -5 and +1: \((-5)\times1 = -5\) and \(-5 + 1 = -4\).

Step3: Write factored form

So, \(x^{2}-4x - 5=(x - 5)(x + 1)\).

Answer:

D. \((x - 5)(x + 1)\)