Question

The model represents x2 – 9x + 14.

Answer 1

Factorize the quadratic trinomial $x^2 - 9x + 14$ by the rule:

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

1. Find the roots:

$D=(-9)^2-4\cdot 14=81-56=25,\ \sqrt{D}=5,\\ \\ x_1=\dfrac{9-5}{2}=2,\ x_2=\dfrac{9+5}{2}=7.$

2. Factorize the polynomial:

$x^2 - 9x + 14=(x-2)(x-7).$

3. Only factor x-2 is given in options, then the correct choice is B.

Answer 2

The factored form of x2 - 9x +14 
(x-2)*(x-7) 
so the answer is B.(x-2)