x^4 - 81

i got x = - 3, +3

how do you write that in interval notation tho? [-3,-3] U [3,3] ? have no idea what im doing..

Question

x^4 - 81

i got x = - 3, +3

how do you write that in interval notation tho? [-3,-3] U [3,3] ? have no idea what im doing..

turingtest · Answer

x^4=81
you mean?

anonymous · Answer

x^4 - 81 > 0

anonymous · Answer

so then i did x^4 -81 = 0 then x^4 = 81 took the fourth root of both sides and got plus or minus three did the number line stuff and found that only -3 / 3 work so did i mess up or whaatt

anonymous · Answer

$$x<-3$$$$x>3$$

In interval notation $$(-\infty,-3)\cup(3,\infty)$$

anonymous · Answer

You need to check both sides of your answer (3,-3) to see which way the inequality goes :)

anonymous · Answer

oh okay thanks i just realized what i did wrong! i messed up with my math but thank you so muchh!