Using the quadratic formula, Solve this equation h^2-2h=8 .. So x = ?

Question

solomonzelman · Answer

$\large\color{slate}{ h^2-2h=8    }$

add 1 to both sides,
$\large\color{slate}{ h^2-2h\color{red}{+1}=8\color{red}{+1}    }$

you get:
$\large\color{slate}{ h^2-2h+1=8+1    }$           NOW, complete the square.

solomonzelman · Answer

(And you know what 8+1 is)

anonymous · Answer

9 !

misty1212 · Answer

HI!!

anonymous · Answer

Dont you need to square root, 3 is not the right answer.. so confused

misty1212 · Answer

if you really want to use the quadratic formula, rather than completing the square (which would be easier in this case) then the first thing you need to do is write 
$$h^2-2h-8=0$$ then use 
$$h=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$$ with 
$$a=1,b=-2,c=-8$$

solomonzelman · Answer

you can factor it

misty1212 · Answer

it would be easier to complete the square, still easier to factor 
$$h^2-2h-8=(h+2)(h-4)$$

solomonzelman · Answer

completing the square was the first that came on my mind.