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x ^ 2 +12x +12 = 0
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.
r + s = -12 rs = 12
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 = -6 - u s = -6 + u
Two numbers r and s sum up to -12 exactly when the average of the two numbers is \frac{1}{2}*-12 = -6. 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>
(-6 - u) (-6 + u) = 12
To solve for unknown quantity u, substitute these in the product equation rs = 12
36 - u^2 = 12
Simplify by expanding (a -b) (a + b) = a^2 – b^2
-u^2 = 12-36 = -24
Simplify the expression by subtracting 36 on both sides
u^2 = 24 u = \pm\sqrt{24} = \pm \sqrt{24}
Simplify the expression by multiplying -1 on both sides and take the square root to obtain the value of unknown variable u
r =-6 - \sqrt{24} = -10.899 s = -6 + \sqrt{24} = -1.101
The factors r and s are the solutions to the quadratic equation. Substitute the value of u to compute the r and s.