Help me with these answers and please number which question you’re doing so I don’t get confused

7a:

7b:

Step-by-step explanation:

If we have two systems of equations, we need to find the value that satisfies both expressions.

To solve this, we can make one expression equal to the other.

The first expression will be , since there is a flat fee of 40$ and you're charged 60$ per month.

The second expression will be as there is no flat fee and you are charged 80$ per month.

So we have the equation .

To solve for this equation, we want to isolate m on one side.

Let's subtract 60m from both sides:

Now let's divide both sides by 20:

Hope this helped!

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: