Check the picture below.
so.. notice, the box for the gift is really just a rectangular prism, which is really just 6 rectangles stacked up to each other at the edges.
the front and back are two 5x3 rectangles
the left and right are just two 3x7 rectangles
and the top and bottom are just two 5x7 rectangles
so, just get the area of each, sum them up, and that's the area of the rectangular prism and thus of the box, and that's how many in² she will need.
Answer:
1.5 inches/ week
Step-by-step explanation
Given
Height of he plant = 3in
If the plant grows by 2in every week
The rate of change = Height of plant/weekly increase
The rate of change = 3/2 = 1.5 inches/ week
You can use a tangent:

We have opposite = 17 and adjacent = x.

substitute:
cross multiply
multiply both sides by √3

divide both sides by 3

Use the Pythagorean theorem:

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Other method.
triangle.
The sides are in the ratio 
Therefore

Use two pints on the graph to find the slope:
(0,0) and (5,1)
Slope = Change in Y over the change in x.
Slope = (1-0) / (5-0) = 1/5 = 0.20
The slope of the given equation is 0.25 which is greater than 0.20.
The unit rate is greater in the equation.