Unusual Solution Sets

[nycmathguy]

Section 2.7
38 & 40

Question 38

The solution set of x^2 + 3x + 8 > 0
consists of the entire set of real numbers, (−∞, ∞). The value of the quadratic polynomial x^2 + 3x + 8 is positive for every real value of x.

Question 40

The solution set of x^2- 8x + 16 > 0
is empty. The polynomial x^2 + 3x + 16 is not greater than zero for any value of x.

You say?

 

[MathLover1]

38. correct

40. correction: the solution set is not empty, it is , (−∞, ∞) just has one hole at x=4
so, , (−∞, 4) U , (4 ∞)

 

[nycmathguy]

38. correct

40. correction: the solution set is not empty, it is , (−∞, ∞) just has one hole at x=4
so, , (−∞, 4) U , (4 ∞)

Thank you for pointing out my error per thread.