0,6x+9x2=0

It looks like you mean 0.6x + 9x^2 = 0.

Solve:

• Factor out x: x(9x + 0.6) = 0
• Solutions: x = 0 or 9x + 0.6 = 0 ⇒ x = -0.6/9 = -1/15

Final answer: x = 0 or x = -1/15 (approximately -0.0667).