factor x^2-4x-12 in the form of x^2+bx+c

Question

anonymous · Answer

This is expanded form, not factored: x^2+bx+c

o_O

mathslover · Answer

hello @PatriciaMae  first of all welcome to openstudy : 

$$\huge{x^2-4x-12}$$ 
$$\huge{x^2+bx+c}$$ 

b = -4 and c = 12 it is already inthe form of x^2+bx+c

anonymous · Answer

It can however be factored:

Let:
1 = a
-6 + 2 = -4  = b
-6 * 2 = -12  = c

So therefore:
$$(x-6) (x+2)$$

Check it by putting back in expanded form:
(x-6) (x+2)
F . O . I . L . 
(x)(x) + (x)(2) + (-6)(x) + (-6)(2)

unklerhaukus · Answer

to factor an expression in the form
$$ax^2+bx+c$$

use the quadratic formula
$$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$$

anonymous · Answer

@UnkleRhaukus , that works for all values of x for quadratic equations, but I do feel:
1.  Factoring is easier and faster here.  :-)  (personal opinion)
2.  What she wrote was in expression not an equation, the quadratic equation needs:
ax^2 + bx + c = 0

If you need to solve for when that whole quadratic polynomial is equal to zero as an equation, then either factoring or the quadratic equation works here: 
(x-6)(x+2)=0
x-6=0  -or-  x+2=0
x=6  -or-  x=-2