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

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Answer 1 · 2018-06-14T13:53:14

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

$25x^2 + 30x = 12$

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

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

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

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

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

How do you solve the quadratic equation by completing the square: 25x^2+30x=1225x^2+30x=12?