# Thread: find the range of values for p inequality question

1. ## find the range of values for p inequality question

Find the range of values of p for which the equation x^2 - 6x + p^2 =0 has real roots

I got till this part :
p^2 <= 9
How do I get that? THANK YOU!

2. ## Re: find the range of values for p inequality question

Originally Posted by pumbaa213
Find the range of values of p for which the equation x^2 - 6x + p^2 =0 has real roots
The answer is -3<=p<=3 How do I get that? THANK YOU!
Use the discriminate: $\displaystyle 36-4p^2>0$ .

3. ## Re: find the range of values for p inequality question

Sorry im still unsure can you help me further? Thank you!
Why can't The answer be p<=3 OR p<= -3 ? How does it become -3<= p <= 3 ? Thank you!

4. ## Re: find the range of values for p inequality question

Originally Posted by pumbaa213
Sorry im still unsure can you help me further? How does it become -3<= p <= 3 ? Thank you!
It is basic algebra. You need to be able to do simple elementary algebra in order to work at this level.

Maybe you ought to speak to your instructor?

5. ## Re: find the range of values for p inequality question

Originally Posted by pumbaa213
Sorry im still unsure can you help me further? Thank you!
Why can't The answer be p<=3 OR p<= -3 ? How does it become -3<= p <= 3 ? Thank you!
Think of the number 0 for example. This is \displaystyle \displaystyle \begin{align*} \leq 3 \end{align*}, but it's not \displaystyle \displaystyle \begin{align*} \leq -3 \end{align*}. How are you supposed to know which is correct?

6. ## Re: find the range of values for p inequality question

p^2<=9 so p<=sqrt 9 or next part we change the sign wen we take negatve sqrt 9 so p<=3 or p>=-3

-3<=p<=3

7. ## Re: find the range of values for p inequality question

Ok I ve got it..! Thanks guys! :-)