How do you solve $3x^2 = -12x - 15$ ?

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Answer 1 · 2016-01-17T15:19:46

$x=-2+-i$

Move the terms to the same side of the equation.

$3x^2+12x+15=0$

Divide both sides by $3$ .

$x^2+4x+5=0$

$x=(-4+-sqrt(4^2-4(1)(5)))/2$

$x=(-4+-sqrt(-4))/2$

As you can now see, this equation only has complex (imaginary) roots.

$x=(-4+-2i)/2$

$x=-2+-i$

How do you solve 3x^2 = -12x - 153x^2 = -12x - 15?