Posted by **Charly** on Thursday, June 2, 2011 at 10:03am.

I was given this answers to a problems I solved but I do not understand what she means hope you can help.

Before attempting to solve this quadratic equation, determine how many solutions there will be for this quadratic equation. Explain your reasoning. Finally, solve the equation.

(x - 9)2 = 81

I too, came up with the same answer and agree that this is a positive number and we should expect there to be two solutions to this problem. Carrying out the square is exactly the same as using the quadratic formula it is where you substitute a, b and c into the formula. It gives you the same answer to the polynomial used. This is because the quadratic formula came from finishing the square. Completing the square method is like the father of the quadratic formula.

(x - 9)2 = 81

(x - 9) = 81

x = 9}9

x = 18 or x = 0

This answer was inreponce to another student who came up with the same as i did.

Hi Charly,

Yes, your answer is correct. Nice work. However, the method you used is not completing the square. Which one might it be, do you think?

- Algebra -
**PsyDAG**, Thursday, June 2, 2011 at 11:58am
For you information, online "^" indicates an exponent, e.g., x^2 = x squared.

(x - 9)^2 = 81

x^2 -18x + 81 = 81

x^2 - 18x = 0

x(x-18) = 0

X = 18 or 0

## Answer this Question

## Related Questions

- Algebra - I was given this answers to a problems I solved but I do not ...
- Math - Solve the given quadratic equation exactly using the quadratic formula. ...
- Math - Solve the given quadratic equation exactly using the quadratic formula. ...
- Algebra II - 1)What method(s) would you choose to solve the equation: x2 + 2x - ...
- algebra - Why are there two solutions in the quadratic equation and Why do you ...
- Algebra problems - I have some problems that I would like checked please. Find ...
- math algebra - Part 1: Which part of the quadratic formula tells you whether the...
- algebra II - How do you know if a quadratic equation will have one, two, or no ...
- algebra II - How do you know if a quadratic equation will have one, two, or no ...
- Math - I'm using the quadratic equation and I understand how to use it, but the ...

More Related Questions