If 5x + x² > 100, then x is not?

10,8,7, or 9

4 Answers

Relevance
  • 8 years ago

    5x + x² > 100

    ==========================================

    5(10) + (10)² = 50 + 100 = 150, which is greater than 100.

    5(9) + (9)² = 45 + 81 = 126, which is greater than 100.

    5(8) + (8)² = 40 + 64 = 104, which is greater than 100.

    5(7) + (7)² = 35 + 49 = 84, which is less than 100.

    Therefore, the answer is 7.

  • Steven
    Lv 7
    8 years ago

    5x + x² > 100

    plug in the numbers

    10

    50+100

    8

    40+64

    7

    35+49

    x is not 7

  • Anonymous
    8 years ago

    just plug and chug ...

    if x = 10, then 5x + x^2 = 150 .... which is >100, so that's still true

    if x = 8, then 5x + x^2 = 40+64 = 104, which is also true.

    therefore 9 would also have to be true.

    it's not 7 by process of elimination or you can calculate it and see it = 84 which is less than 100

  • DWRead
    Lv 7
    8 years ago

    7

Still have questions? Get your answers by asking now.