Justin is saving money to buy a stereo. He has $25 saved in the bank right now. He earns $40 each week delivering newspapers. Let y = the total amount of money Justin has, and x is in weeks.

Write an equation for how much money Justin has (including the amount he has in the bank) in x weeks.:

y = 25 + 40x

Step-by-step explanation:

Let

y = the total amount of money Justin has

x = number of weeks

Amount Justin has in the bank = $25

Amount Justin earns per week = $40

Equation for how much money Justin has (including the amount he has in the bank) in x weeks

the total amount of money Justin has = Amount Justin has in the bank + (Amount Justin earns per week * number of weeks)

y = 25 + (40 * x)

y = 25 + 40x

The equation is

y = 25 + 40x

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:

12.5 feet

step-by-step explanation: