# [SOLVED] Quadratics setting on cacluator

• September 26th 2008, 02:50 AM
TheHour
Hi,

I am trying to work out some quadractic equations when I compare the my answer to the answer book it is wrong. I even typed in the exact example they gave me. My calculator screen is attached is it in the right settings?

Thanks
• September 26th 2008, 05:10 AM
masters
Quote:

Originally Posted by TheHour
Hi,

I am trying to work out some quadractic equations when I compare the my answer to the answer book it is wrong. I even typed in the exact example they gave me. My calculator screen is attached is it in the right settings?

Thanks

Why are you using a calculator to solve a quadratic equation? Just factor the thing or use the quadratic formula.
• September 26th 2008, 06:12 AM
TheHour
I need the calculator for the formula

When I substitute a, b and c the answer is I get on my calculator is different to the answer in the answer book I know the theory is correct. Would you like to see my workings

Thanks
• September 26th 2008, 06:18 AM
masters
Quote:

Originally Posted by TheHour
I need the calculator for the formula

When I substitute a, b and c the answer is I get on my calculator is different to the answer in the answer book I know the theory is correct. Would you like to see my workings

Thanks

That would be nice.
• September 26th 2008, 06:40 AM
TheHour
Here it is

Thanks
• September 26th 2008, 07:09 AM
masters
Quote:

Originally Posted by TheHour
Here it is

Thanks

$\frac{-5+\sqrt{17}}{2}=-.438$

$\frac{-5-\sqrt{17}}{2}=-4.562$
• September 26th 2008, 07:20 AM
TheHour
So its my calculator as I worked out

$\frac{-5+\sqrt{17}}{2}$

$\frac{-5-\sqrt{17}}{2}$

on my calculator and it gave me the results in the image above. The settings on the caluclator are in my first post, im sure I have reset the settings by mistake. Looks like my method is fine though just the working out wich wasn't even done by me :)

Thanks
• September 26th 2008, 07:26 AM
masters
Quote:

Originally Posted by TheHour
So its my calculator as I worked out

$\frac{-5+\sqrt{17}}{2}$

$\frac{-5-\sqrt{17}}{2}$

on my calculator and it gave me the results in the image above. The settings on the caluclator are in my first post, im sure I have reset the settings by mistake. Looks like my method is fine though just the working out wich wasn't even done by me :)

Thanks

You have to be careful when you enter things in a calculator. You probablly did not pair all your parentheses. Try it this way:

Be sure to put the entire numerator in parentheses before you divide by 2.

My solutions in Post #6 are correct. What does your book say?
• September 26th 2008, 07:58 AM
TheHour
You where correct as the answers say -0.438 or -4.562.

While typing this I remember the way I am working it out I need brackets, im not typing it in as a fraction as you did, im just doing it as one line, doh. All fixed