If 5x + x² > 100, then x is not?
Notice if x=7 then 5*7+7^2=35+49=84… So x is not 7
If you plug in each answer for the value of x, then answer C (the number 7) is the only one that works. If 5x + x^2 cannot be greater than 100, then 5(7) + (7)^2 = 84, which is less than 100. All other answers give a number greater than 100, which makes the inequality work.