# Math Help - Quadratic Formula Help

Im really not sure if this is calculus and I know this is really simple but this is the one thing that has always confused me so help me out...

x^2+40x-40=0

what is x?
haha thanks

2. Originally Posted by Gman8990
Im really not sure if this is calculus and I know this is really simple but this is the one thing that has always confused me so help me out...

x^2+40x-40=0

what is x?
haha thanks
It can be written as $(x + 20)^2 - 400 - 40 = 0$ ....

3. Originally Posted by Gman8990
Im really not sure if this is calculus and I know this is really simple but this is the one thing that has always confused me so help me out...

x^2+40x-40=0

what is x?
haha thanks
Since you titled this "Quadratic Formula Help", do you know what the quadratic formula is?

If $ax^2+ bx+ c= 0$ then

$\frac{-b\pm\sqrt{b^2- 4ac}}{2a}$

Here a= 1, b= 40 and c= -40.

Of course, mr. fantastic's completing the square works nicely too.