tkhunny, Just a Bit More Help, Please ...

[Guest]

Dear tkhunny,

Thank you so much for your speedy reply. Just a bit more help, please, if you would be so kind.

5*x^2 + 10*x +1 = 0

THAT is ready for the Quadratic formula. If you get x = -2 or x = 0, just throw them out.

It is precisely at this point that she is getting stuck, i.e., the answer she gets does not match the answer key.

Would you please show the application of the quadratic formula to the equation in solving for x? Thanks so much!!

 

[tkhunny]

This is an excellent example of missing information. If you didn't need any help getting your equation to look like this, you should have said so. It would have saved me 10-15 minutes.

The form is a*x^2 + b*x + c = 0

Identify:
--- a = 5
--- b = 10
--- c = 1

Then [-b + sqrt(b^2 - 4*a*c)]/2*a = [-10 + sqrt(10^2 - 4*5*1)]/2*5
And [-b - sqrt(b^2 - 4*a*c)]/2*a = [-10 - sqrt(10^2 - 4*5*1)]/2*5

Simplify as possible.