The solutions of the equation are x=-3+√42 and x=-3-√42.
The given quadratic equation is 2x²+12x=66.
What is completing square method?
Completing the Square is a method used to solve a quadratic equation by changing the form of the equation so that the left side is a perfect square trinomial.
Now, 2x²+12x=66 can be written as x²+6x-33=0
Add and subtract (b/2)² to the equation.
That is x²+6x-33+9-9=0
⇒x²+6x+9=42
⇒(x+3)²=42
⇒(x+3)=±√42⇒x=±√42-3
Therefore, x=-3+√42 and x=-3-√42.
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https://brainly.com/question/2263981.
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