# How do you solve the quadratic equation by completing the square: 25x^2+30x=12?

Jun 14, 2018

color(red)(x = (sqrt21-3)/5, -(sqrt21 + 3) / 5

#### Explanation:

$25 {x}^{2} + 30 x = 12$

$25 {x}^{2} + 30 x + 9 = 12 + 9$

${\left(5 x + 3\right)}^{2} = 21$

${\left(5 x + 3\right)}^{2} = {\left(\sqrt{21}\right)}^{2}$

$5 x + 3 = \pm \sqrt{21}$

color(red)(x = (sqrt21-3)/5, -(sqrt21 + 3) / 5