SOLUTION: What is the solution of the inequality 9 - x^2 < 0? (a) {x | -3 < x < 3} (b) {x | x > 3 or x < -3} (c) {x | x | x > 3} (d) {x | x < -3} I think it's either choice b or c, bu

Algebra ->  Inequalities -> SOLUTION: What is the solution of the inequality 9 - x^2 < 0? (a) {x | -3 < x < 3} (b) {x | x > 3 or x < -3} (c) {x | x | x > 3} (d) {x | x < -3} I think it's either choice b or c, bu      Log On


   

Question 1011501: What is the solution of the inequality 9 - x^2 < 0?
(a) {x | -3 < x < 3}
(b) {x | x > 3 or x < -3}
(c) {x | x | x > 3}
(d) {x | x < -3}
I think it's either choice b or c, but I'm not sure. Please show how you got the answer. Thank you!
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Let's first isolate x^2

9 - x^2 < 0
9 - x^2+x^2 < 0+x^2
9 < x^2
x^2 > 9

Now we will apply the square root function to both sides

x^2 > 9
sqrt(x^2) > sqrt(9)
|x| > 3 ... take note of the absolute value

The inequality |x| > 3 breaks down into these two inequalities

x > 3 or x < -3

So the answer is choice B