# How do you solve #9d^2-81=0#?

##### 1 Answer

Oct 2, 2017

You can factor out 9 immediately:

Or, you can plug the coefficients from the original equation into the quadratic formula. Remember this will solve any quadratic having of form

...substitute 'd's for x's, and use a = 9, b = 0, c = -81.

and plug 'em into the quadratic formula:

remember that coefficient b is zero for this case, so we get:

(I think the first way is easier, but hey.)

GOOD LUCK!