What is that $13,455.78? Something? I did this and got $13,122.76. Here's how I did it:
Use this formula

where A is the ending amount, P is the starting amount, n is the number of times it compounds a year, and t is the number of years. We have all we need to set it up:

First divide and add inside the parenthesis:

then multiply the exponents:

raise the value inside the parenthesis to the power of 260:

and finally multiply to get A = $13,122.76
1a is right
In 1b, add the tax, don't subtract, the answer would be 36.04
2a) 32.5*.2=6.5
2b)32.5-6.5=26
3a)12.5*.13=1.63
3b)13.83
4a)59.996
4b)89.4
Answer:
A cross section perpendicular to the base would "cut" the prism through the height and width of the prism.
This would make a rectangle, with two sides the same length as the base ( 2 ft) and 2 sides the height of the prism ( 12 ft).
The answer would be:
A rectangle with two 12-ft sides and two 2-ft sides.
Slope-intercept form is y = mx +b, where the variable m represents the slope of the line and the variable b represents the y-intercept of the line. Since we weren't given the y-intercept, one way to solve this problem is substitute the slope for the variable m and then the x and y values from the ordered pair to solve for b.
y = mx + b
y = 3x + b
-4 = 3(9) + b
Now, we can simplify by computing the multiplication on the right side of the equation.
-4 = 27 + b
Finally, we can find the value for b by subtracting 27 from both sides of the equation to get:
-31 = b
Now, we should substitute this value for b back into our equation with the slope.
y = 3x - 31
Therefore, your answer is y = 3x - 31.
Hope this helps!