Question

The factorization of x2 + 3x – 4 is modeled with algebra tiles.

Answer 1

X² + 3x - 4

factors of x² are x * x
factors of -4 that will result to a +3

4 * -1 = -4
4 - 1 = 3

(x + 4) and (x - 1)

x(x-1) + 4(x-1)
x² - x +4x - 4
x² + 3x - 4

Answer 2

The quadratic trinomial can be factor using the following formula:

$ax^2+bx+c=a(x-x_1)(x-x_2), \text{ where } x_1,\ x_2 \text{ are trinomial roots}$.

1. For the quadratic trinomial $x^2 + 3x - 4$ find the roots:

$D=3^2-4\cdot (-4)=9+16=25,\ \sqrt{D}=\sqrt{25} =5,\\ \\ x_1= \dfrac{-3-5}{2} =-\dfrac{8}{2}=-4,\ x_2=\dfrac{-3+5}{2} =\dfrac{2}{2}=1$.

2. The factoring form of trinomial is

$x^2+3x-4=(x+4)(x-1)$.

3. The factors are x+4 and x-1

Answer: correct choice is C.