If X is negative, is X < -3?
My note: This is a yes/no question. X can be anything negative.
1. X^2 > 9
I took the square root of both sides and got X > +/-3
Since X is negative, the first option (X > +3) is out.
Why is the second option (x > -3) wrong? Why is it not X > -3? I don't understand how the results are x>3 or x < -3. I didn't divide or multiply both sides by a negative number, so I don't understand why the sign changes from X > - 3 to X < -3. Please help me understand this concept. Should I not square both sides here?
Thanks very much.
EDIT: I think I got it. Drawing a number line helps. I tested -4 and it it makes sense and I see it now. I X would be LESS than -3.
My note: This is a yes/no question. X can be anything negative.
1. X^2 > 9
I took the square root of both sides and got X > +/-3
Since X is negative, the first option (X > +3) is out.
Why is the second option (x > -3) wrong? Why is it not X > -3? I don't understand how the results are x>3 or x < -3. I didn't divide or multiply both sides by a negative number, so I don't understand why the sign changes from X > - 3 to X < -3. Please help me understand this concept. Should I not square both sides here?
Thanks very much.
EDIT: I think I got it. Drawing a number line helps. I tested -4 and it it makes sense and I see it now. I X would be LESS than -3.
