Answer:
The equation that matches the function shown is option;
C. 
Step-by-step explanation:
The given graph of the function is a sinusoidal graph
The values of 'x' and 'y' coordinates at the maximum, x-intercept and minimum points are given as follows;
x,
y
0
0
π
1
2·π
0
3·π
-1
4·π
0
We note that sin(π/2) = 1, sin(π) = 0 sin(3·π/2) = -1, and sin(4·π/2) = sin(2·π) = 0
Therefore;
y = the sine of half the x-value
Which is presented as follows;
.
The surface area (SA) of a cube can be written as:
SA = 6s²
From here we can write, the length of the side s as:

For cube with surface area of 1200 square inches, the side length will be:

inches
For cube with surface area 768 square inches, the side length will be:

inches
The difference in side lengths of two cubes will be:
Rounding to nearest tenth of an integer, the difference between the side lengths of two cubes will be 2.8 inches.
The sign of the product of that equation would be negative.