Select the best estimate that would help you check the answer to 778×23 .

A.

700×30

B.

700×20

C.

800×20

D.

800×30

C: 800 x 20

Step-by-step explanation:

Basically, when you round 778 you see that the 7 and 8 are above 5, which means you round upwards. Therefore it would be best to round up to 800.

Then the 3 in 23 is below 5, meaning you round downwards. 20 Is the closest and best option.

So, C: 800 x 20 is best to do!

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:

98%

step-by-step explanation: