Question

For which value would the graph y= x^4 -25 be below the x axis?

Answer 1

well, below the x-axis is y < 0 so x^4 would have to be less than 25.

x^4 < 25
(x^2)^2 < 5^2
x^2 < 5
x < sqrt(5)
~ 2.23
answer has to be 1