Hi,
f(1)=16
f(2)=f(1)+2*2=16+4=20
f(3)=f(2)+2*3=20+6=26
f(4)=f(3)+2*4=26+8=34
To find surface area, you would find the area of each side of the shape. Since this is a cube, each side is a square. So area=side2, So each side is 9, so 9x9=81 for each face. There are 6 faces to a cube, so 6x81=486 in2 is your answer
It looks like he used the distributive property. He multiplied 7*2. Then. 7*6. Then he multiplied them together. That is not how you multiply numbers
Answer: x=7 and AC = 44 unuts.
Step-by-step explanation:
We know that the diagonals of a parallelogram bisect each other. (i)
Here in parallelogram ABCD , AC and Bd are diagonals intersecting at E.
BE = 2x + 2, BD = 5x – 3, and AE = 4x – 6
Using (i)

Now , AE = 4(7)-6 = 28-6 = 22
AC =2 AE = 2 (22) =44 units.
Hence, x=7 and AC = 44 unuts.
The critical points are at x = 1 and x = 4 giving you the intervals (-inf, 1), (1, 4) and (4, inf).
By substituting x values in these 3 intervals, you can see that f'(x) is positive in the first and third intervals and negative in the second interval.
This means that f(x) is increasing in the first and third intervals and decreasing in the second interval.
The answer is D.