please help me to understand how this problem was solved. if you aren't going to explain don't even bother. no trolling :0

see below

Step-by-step explanation:

In the first step, they added 28 to both sides of the equation to get rid of the -28 on the left side. Next, they subtracted 4x from both sides to get rid of the 4x on the left side. They are doing this so that they can isolate y on one side. Isolating y basically means that you need to get all of the y terms on one side and all of the non-y terms on the other side. Next, they divided the entire equation by 8 to get rid of the 8 in 8y. Finally, since y and f(x) are the same thing, they simply substituted f(x) for y.

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:

1/2*qr*rs

step-by-step explanation: