x2 + 4x – 12 = 0 by completing the square.

Question

anonymous · Answer

add 12 to both sides
$$x^2+4x=12$$ take half of 4 which is 2 and write 
$$(x+2)^2=12+2^2=12+4=16$$
$$(x+2)^2=16$$
take the square root and get 
$$x+2=4$$ or 
$$x+2=-4$$ so 
$$x=2$$ or 
$$x=-6$$

anonymous · Answer

Gracias :)

anonymous · Answer

welcomas

anonymous · Answer

if it didnt have = 0 would it be 

 Ex. of a diff problem,  x = 16 -4 +/- 2 sqrt3 = x + 4

anonymous · Answer

? i think you lost me

anonymous · Answer

Nevermind lol

anonymous · Answer

k

anonymous · Answer

can yu help me with this...

 how you would use the quadratic formula to solve x2 + 5x = –2. Why is the quadratic formula the best method to use?

anonymous · Answer

it is the best method to use because if you complete the square you are going to get annoying fractions

anonymous · Answer

solve 
$$x^2+5x+2=0$$ via 
$$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$$ with 
$$a=1,b=5,c=2$$

anonymous · Answer

if you see 
$$x^2+6x-1=0$$ complete the square because half of 6 is 3

anonymous · Answer

but if you see 
$$x^2+7x-2=0$$ might as well use the formula because half of 7 is 7/2 and it will be kind of messy

anonymous · Answer

i am off.  good luck!

anonymous · Answer

:)