So hmm notice the picture below
the pyramid itself, is really, just one regular hexagon, at the bottom
and 6 triangles, stacked up at each other at the edges
now, if you just get the area of the regular hexagon, and the 6 triangles, add them up, that'd be the total surface area of the pyramid then

now, for the triangles, well, area of a triangle is 1/2 bh, as you'd know, and you have both
In the monthly payment formula r is the percentage rate as a decimal.
To turn a percentage into a decimal, move the decimal point 2 places to the left.
5.7% becomes 0.057
The sum is 12x3+18x2-10x+8
Exercise 1:
exponential decay:
The function is given by:
y = A (b) ^ ((1/3) * t)
Where,
A = 600
We look for b:
(480/600) * (100) = 80%
b = 0.8
Substituting:
y = 600 * (0.8) ^ ((1/3) * t)
We check for t = 6
y = 600 * (0.8) ^ ((1/3) * 6)
y = 384
Answer:
exponential decay:
y = 600 * (0.8) ^ ((1/3) * t)
Exercise 2:
linear:
The function is given by:
y = ax + b
Where,
a = -60 / 2 = -30
b = 400
Substituting we have:
y = -30 * x + 400
We check for x = 4
y = -30 * 4 + 400
y = 280
Answer:
linear:
y = -30 * x + 400
Exercise 3:
exponential growth:
The function is given by:
y = A (b) ^ ((1/3) * t)
Where,
A = 512
We look for b:
(768/512) * (100) = 150%
b = 1.5
Substituting:
y = 512 * (1.5) ^ ((1/2) * t)
We check for t = 4
y = 512 * (1.5) ^ ((1/2) * 4)
y = 1152
Answer:
exponential growth:
y = 512 * (1.5) ^ ((1/2) * t)
The second, 4th and 6th ones are the correct answers.