Answer please thanks

(2A /h) - b1 = b2

Step-by-step explanation:

A = 1/2 h ( b1 + b2)

Multiply each side by 2

2A = 2*1/2 h ( b1 + b2)

2A =  h ( b1 + b2)

Divide each side by h

2A/h= h/h ( b1 + b2)

2A/h=  b1 + b2

Subtract b1 from each side

2A /h - b1 = b2

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:

the correct answer is d

hope this