# Can you check my homework? (quadratic formulas

• Jul 15th 2013, 03:28 PM
Urpes
Can you check my homework? (quadratic formulas
Attachment 28830 Attachment 28831Attachment 28832Attachment 28833

The question also states that I should leave my answers in 'radical' form? What is that?
• Jul 15th 2013, 03:47 PM
Re: Can you check my homework? (quadratic formulas
Be careful with radicals. Do not simplify whatsoever with stuff like root 5 unless told so, and you were told in this problem to stay in radical form. Also, the square root of -16 is 4i
• Jul 15th 2013, 03:59 PM
Urpes
Re: Can you check my homework? (quadratic formulas
Quote:

Be careful with radicals. Do not simplify whatsoever with stuff like root 5 unless told so, and you were told in this problem to stay in radical form. Also, the square root of -16 is 4i

Okay so if I don't root the 5, is the answer on the third step? Also if I don't root the 5 is it still okay to root the 14 in question 1?

I don't understand what a radical is, and what my boundaries are

Also should I be typing x= for every step?
• Jul 15th 2013, 04:57 PM
Re: Can you check my homework? (quadratic formulas
root 14 is a mistake, as it should just be 14. The square root of 196 is 14, not root 14. What is square root is is the opposite of squaring a number. For example, if 3 squared (3*3 or 3^2) = 9 and the square root of 9 = 3. For number 2, the third step would be the answer. Also, for the third question, do you understand what i is?
• Jul 15th 2013, 05:19 PM
topsquark
Re: Can you check my homework? (quadratic formulas
This is a mess. What I propose is, for the next day or so (or until Urpes is satisfied), to only post comments about the first two problems then do the other two.

-Dan
• Jul 15th 2013, 05:59 PM
Urpes
Re: Can you check my homework? (quadratic formulas
Quote:

Also, for the third question, do you understand what i is?

I don't really understand what it is but I believe I'm supposed to put it there when the number in the root is negative.

How do I know I'm not supposed to simplify the 5 in question 2? Is it because it doesn't work out to a complete number when you square it?
Quote:

Originally Posted by topsquark
This is a mess. What I propose is, for the next day or so (or until Urpes is satisfied), to only post comments about the first two problems then do the other two.

-Dan

I apologize, again... We just started using the quadratic formula, and substitution today, and I have a test on it tomorrow afternoon.... thats why I'm in quite a hurry to verify my answers.
• Jul 15th 2013, 06:26 PM
Prove It
Re: Can you check my homework? (quadratic formulas
First of all, the square root symbol has to go over the ENTIRE \displaystyle \begin{align*}
\sqrt{b^2 - 4ac} \end{align*}
, not just \displaystyle \begin{align*} \sqrt{b^2} - 4ac \end{align*}. However, due to how you have continued to simplify, I think that you already knew this and just had trouble actually typing this out.

In the first, \displaystyle \begin{align*} \sqrt{100 + 96} = \sqrt{194} = 14 \end{align*}, not \displaystyle \begin{align*} \sqrt{14} \end{align*}.

You should take note that we use the Quadratic Formula to get EXACT answers. This means in the second you really should keep it in terms of \displaystyle \begin{align*} \sqrt{5} \end{align*} unless you're told to try to get a decimal approximation. Otherwise the second is correct.

In the third, you would either get to \displaystyle \begin{align*} \sqrt{-16} \end{align*} and say there are no real solutions (as you can not take the square root of a negative number to get a real number), or if you are allowed to have complex solutions, write \displaystyle \begin{align*} \sqrt{-16} = 4i \end{align*} and go from there.

In the last, surely you can see that \displaystyle \begin{align*} 144 - 144 = 0 \end{align*}, so that means you will be adding and subtracting 0, giving the SAME number. So you should only be getting ONE solution.
• Jul 15th 2013, 06:30 PM