# How do you solve by completing the square for 3x^2-12x+1?

May 29, 2015

$3 {x}^{2} - 12 x + 1$ if you add 8 than it will be like;
$3 {x}^{2} - 12 + 9 = \left(3 x - 3\right) \cdot \left(x - 3\right)$ this is as far as i get.
But i think that some info is missing with that question. To completely solve this question;
$3 {x}^{2} - 12 x + 1 = A \implies$ we should know this "A" value.
Since you didn't write that A value i cannot entirely solve the question . I 'm sorry :)

May 29, 2015

I will assume that what you really want to solve (by completing the square) is $3 {x}^{2} - 12 x + 1 = 0$

$3 {x}^{2} - 12 x + 1 = 0$

${x}^{2} - 4 x = - \frac{1}{3}$

${x}^{2} - 4 x + 4 = 4 - \frac{1}{3}$

${\left(x - 2\right)}^{2} = \frac{11}{3}$

$x - 2 = \pm \frac{\sqrt{11}}{\sqrt{3}}$

$x = 2 + \frac{\sqrt{11}}{\sqrt{3}}$ or $x = 2 - \frac{\sqrt{11}}{\sqrt{3}}$