Explain how you can use a number line to find the sum of 4+(-8)

-4

Explanation: To add 4 + (-8), we start at 0 on the number line.

4 tells us to move 4 units to the left.

From there, -8 tells us to move 8 units back to the left and you can see from the picture below that we end up at -4.

So 4 + (-8) is -4.

Image is provided below.

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation:

no not all of them.

step-by-step explanation:

some of them have a square base.