## Trending News

# help with the Quadratic formula?

4x^2 - 2x - 1 = 0

using the quadratic formula

i know what the qaudratic formula is and i have done it before but for some reason i keep getting this question wrong so could somebody please show the working out and explain to me??

any help would be greatley appreciated

answer in surd form please

### 5 Answers

- JackoLv 69 years agoFavorite Answer
Using the formula:- x= -b +/- square root of b^2 - 4ac all divided by 2a

In this problem a=4, b=-2, c=-1

So.... x= 2+square root of 4 - 4*-4 all divided by 8

x=2+square root of 4- (-16) all divided by 8

x=2+square root of 4+16/8

x=2+square root of 20/8

x=2+4.47/8

x=6.47/8

x=0.809

You will now have to repeat this substituting the + sign after the 2, with a - sign to get the complete answer.

- Anonymous9 years ago
Quadratic formula ... x= -b +/- √b)2 -4ac

Divided by 2a

X equals the opposite of b plus of minus square root of b square minus four a c divided by two a....

Hope this helps

- How do you think about the answers? You can sign in to vote the answer.