What values are solutions to the inequality below

x^2<81
-
-9
81
5
7
10
no solutions
I'm really confused on this one. Can someone explain which ones are correct and why?

take square root of both sides, keeping in mind that the root could be positive or negative, so
-9 < x < 9

the correct choices are: 5 and 7

i'm not going to answer this for you buy basicaly square all these numbers and see which result in less than 81. for example in your calculator do (-9) raised to the second power then see if the answer is less than 81. remember if the inequality sign has a line under it then it means less than or equal to. if it does not have a little line underneath as shown in your problem it only means less than.

Hi Krista,

You can take square roots by using the modulus function, it means "size of":

x^2 < 81

|x^2| < |81|

|x| < 9.

"Size of x is less than 9."

Then, compare all of your numbers using this:

|-9| < 9 false
|81| < 9 false
|5| < 9 true
|7| < 9 true
|10| < 9 false
no solutions: false, look at 5 or 7.

-----

Solutions:

x = 5 or x = 7.

x^2-81<0
(X-9)(x+9)<0
x-9<0
x+9>0
Because if x^2-81 is less than zero or negative . it means negative times positive is negative .
therefore anyone one term is negative and other term is positive.
So,
x<9
&x>-9
x E ( -9,9)

x^2<81
-9
-

i think the answer should be 5 or 7
cuz 25 and 49 are both less than 81