Answer:
D.
Step-by-step explanation:
The formula is Sum(n) = (n -2) 180.
Part A)
Multiply the amount he earned by 8.5%
8.5% written as a decimal is 0.085.
75,000 x 0.085 = $6,375
Part B)
Subtract the amount of tax from his earnings:
75,000 - 6,375 = $68,625
The angle does not matter. Think of it as finding the other side to a triangle. Use

a=39 (line AB)
b=b (the leg we need to find)
c=89 (line BD)


(subtract the 1521 from both sides)

(square root both sides)

b = 80
AD=80
(3,-8)
You move down from those coordinates
X stays the same while it just moves down only Y changes
The equation that would best describe the situation would be the first option. To solve this question, simply break down the question into sections and then use variables X and y to represent each of the things asked for in the problem. We know the following:
X = no of tetra fish
Y = no of goldfish
If there is twice as much goldfish than tetra fish, then it would be 2y.
X = 2Y.
Then knowing what X and y represent, find the equation that gives the total cost of fish he bought, knowing that 1.50 is for a goldfish and 2.00 is for a tetra fish.