Bob is 9 years younger then joe. three years ago, the sum of their ages was 27. write and solve an equation to determine how old they both are now.

12 and 21

Step-by-step explanation:

Let the age of Bob is x then the age of Joe is x + 9

Three years ago Bob age is x - 3 and Joe is x + 9 - 3 = x + 6

The sum of their ages is (x - 3) + (x + 6) = 27

x - 3 + x + 6 = 27 Add like terms

2x + 3 = 27  Solve equation

2x = 27 - 3

2x = 24

x = 12

Bob = x =12

Joe = x + 9 = 12 + 9 = 21

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: