Question

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

Answer 1

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

Explanation:

`25x^2 + 30x = 12`

`25x^2 + 30x + 9 = 12 + 9`

`(5x + 3)^2 = 21`

`(5x + 3)^2 = (sqrt21)^2`

`5x + 3 = +- sqrt(21)`

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