Question
solve the the following inequality. write your solution in interval notation.
x^3-49x<0
_ (I don't know how to make the sign on my computer)
x^3-49x<0
_ (I don't know how to make the sign on my computer)
Answers
Reiny
x^3 - 49x < 0
x(x^2 - 49) < 0
x(x+7)(x-7) < 0
consider f(x) = x(x+7)(x-7)
the x-intercepts would be -7, 0, 7
Knowing the basic shape of a cubic, we have
x < -7 OR 0 < x < 7
I will let you write that in the interval notation that you learned.
x(x^2 - 49) < 0
x(x+7)(x-7) < 0
consider f(x) = x(x+7)(x-7)
the x-intercepts would be -7, 0, 7
Knowing the basic shape of a cubic, we have
x < -7 OR 0 < x < 7
I will let you write that in the interval notation that you learned.