Solve 6x^2+12x+12

$$6 x ^ { 2 } + 12 x + 12$$

Factor

$$6\left(x^{2}+2x+2\right)$$

Solution Steps

Factor out 6. Polynomial x^{2}+2x+2 is not factored since it does not have any rational roots.

$$6\left(x^{2}+2x+2\right)$$

Steps Using the Quadratic Formula

Quadratic polynomial can be factored using the transformation ax^{2}+bx+c=a\left(x-x_{1}\right)\left(x-x_{2}\right), where x_{1} and x_{2} are the solutions of the quadratic equation ax^{2}+bx+c=0.

$$6x^{2}+12x+12=0$$

All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.

$$x=\frac{-12±\sqrt{12^{2}-4\times 6\times 12}}{2\times 6}$$

Square 12.

$$x=\frac{-12±\sqrt{144-4\times 6\times 12}}{2\times 6}$$

Multiply -4 times 6.

$$x=\frac{-12±\sqrt{144-24\times 12}}{2\times 6}$$

Multiply -24 times 12.

$$x=\frac{-12±\sqrt{144-288}}{2\times 6}$$

Add 144 to -288.

$$x=\frac{-12±\sqrt{-144}}{2\times 6}$$

Since the square root of a negative number is not defined in the real field, there are no solutions. Quadratic polynomial cannot be factored.

$$6x^{2}+12x+12$$

Steps Using Direct Factoring Method

Quadratic equations such as this one can be solved by a new direct factoring method that does not require guess work. To use the direct factoring method, the equation must be in the form x^2+Bx+C=0.This is achieved by dividing both sides of the equation by 6

$$x ^ 2 +2x +2 = 0$$

Let r and s be the factors for the quadratic equation such that x^2+Bx+C=(x−r)(x−s) where sum of factors (r+s)=−B and the product of factors rs = C

$$r + s = -2 rs = 2$$

Two numbers r and s sum up to -2 exactly when the average of the two numbers is \frac{1}{2}*-2 = -1. You can also see that the midpoint of r and s corresponds to the axis of symmetry of the parabola represented by the quadratic equation y=x^2+Bx+C. The values of r and s are equidistant from the center by an unknown quantity u. Express r and s with respect to variable u. <div style='padding: 8px'><img src='https://opalmath.azureedge.net/customsolver/quadraticgraph.png' style='width: 100%;max-width: 700px' /></div>

$$r = -1 - u s = -1 + u$$

To solve for unknown quantity u, substitute these in the product equation rs = 2

$$(-1 - u) (-1 + u) = 2$$

Simplify by expanding (a -b) (a + b) = a^2 – b^2

$$1 - u^2 = 2$$

Simplify the expression by subtracting 1 on both sides

$$-u^2 = 2-1 = 1$$

Simplify the expression by multiplying -1 on both sides and take the square root to obtain the value of unknown variable u

$$u^2 = -1 u = \pm\sqrt{-1} = \pm i$$

The factors r and s are the solutions to the quadratic equation. Substitute the value of u to compute the r and s.

$$r =-1 - i s = -1 + i$$

Evaluate

$$6\left(x^{2}+2x+2\right)$$