Question

David correctly factored the expression m^2 -12m - 64.
Which expression did he write?
(1) (m - 8)(m - 8) (3) (m - 16)(m + 4)
(2) (m - 8)(m + 8) (4) (m +16)(m - 4)
Explain why

Answer 1

Answer:

(3) (m - 16)(m + 4)

Step-by-step explanation:

Given the expression:

m^2 -12m - 64.

Using quadratic formula:

$m = \frac{-b \pm \sqrt{b^2 - 4(a)(c)}}{2(a)}$

$m = \frac{12 \pm \sqrt{(-12)^2 - 4(1)(-64)}}{2(1)}$

$m = \frac{12 \pm 20}{2}$

$m_1 = \frac{12 + 20}{2}$

$m_1 = 16$

$m_2 = \frac{12 - 20}{2}$

$m_2 = -4$

Then, the factored expression is:

(m - 16)(m + 4)