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#