Does anyone know how to do a problem by completing the square? I'm so confused.

Question

mertsj · Answer

We all do.

anonymous · Answer

yes, we do

anonymous · Answer

but best to work with a specific example

mertsj · Answer

Even the Great Satellite stands ready to help you.

anonymous · Answer

example: 4x^2 + 8x + 1
Using a^2 + 2ab + b^2 = (a + b)^2, we have (2x + 1)^2
There's other formulas.

anonymous · Answer

like a^2 - 2ab + b^2 = (a - b)^2

anonymous · Answer

example:3x²-6x-9=0

anonymous · Answer

step number one is to divide by three and get 
$$x^2-2x-3=0$$ then add  3 to both sides and get 
$$x^2-2x=3$$ and now we are ready to "complete the square" although we can also solve this one by factoring

anonymous · Answer

half of -2 is -1 and 
$$(-1)^2=1$$ so you can write 
$$x^2-2x=3$$ and then 
$$(x-1)^2=3+1=4$$
the last step was adding 1 to both sides so that the left hand side is now a perfect square

anonymous · Answer

then solve as 
$$(x-1)^2=4$$
$$x-1=2$$ or 
$$x-1=-2$$ so 
$$x=3$$ or 
$$x=-1$$