Answer:

The best answer for **If 5x + x² > 100, then x is not 10 8 7 9**

Answer is 7

x² + 5x – 100 > 0

Using the quadratic function for x² + 5x – 100 = 0 we get:

x = (-5 ± √425)/2

The decimal approximations are x = -12.8 and x = 7.8

So, the solutions to x² + 5x – 100 > 0 are x < -12.8 or x > 7.8

Therefore, if x is 8, 9 or 10 the inequality does hold true.

Hence, x is not 7