A^2 + 9a - 18 is the simplified version of that equation
Answer:
9m
Step-by-step explanation:
The surface area of a cube is given by
SA = 6s^2 where s is the side length
We know the surface area is 486 and the side length is z
486 = 6z^2
Divide each side by 6
486/6 = 6z^2/6
81 = z^2
Take the square root of each side
sqrt(81) = sqrt(z^2)
9 = z
Each side has a length of 9m
Subtract the new amount from the original amount:
64 - 85 = -21
Now divide that by the original amount:
-21 / 85 = -0.247
Multiply that by 100 for the percentage:
-0.247 x 100 = -24.7%
Rounded to the nearest percent is -25%
I believe the right answer is C, hope this helps