2x2 + 12x = 54 solve by complete the square.

Question

anonymous · Answer

*2^2

anonymous · Answer

$$x ^{2} + 6x = 27$$
$$x ^{2} + 6x + 9 = 36$$
$$(x + 3)(x + 3) = 36$$
$$(x + 3) ^{2} = 36$$
$$x + 3 = 6$$
$$x = 3$$

anonymous · Answer

you may want divide everything by 2 first

anonymous · Answer

x + 3 = + or - 6

wolf1728 · Answer

The method to complete the square:
Move the 'non-x' term to the right
Divide the equation by coefficient of x²

Finally, take the coefficient of x, divide it by 2, then square it.
Add this number to both sides of the equation.

2x2 + 12x = 54 
x² + 6x = 27

6 divided by 2 then squared = 9

Add 9 to both sides of the equation.
That should give you a good start.

anonymous · Answer

but write it as 3^2 on the left... it will remind you (hopefully) of what the factor is...

(x+3)^2