We know that Step 1 is correct, because it is just a restatement of the equation. Therefore, we can eliminate Step 1:
2(5y – 2) = 12 + 6y
In Step 2, the student tried using the Distributive Property. The Distributive Property can be written as one of the two following formulas:
a(b + c) = ab + ac
a(b – c) = ab – ac
In this case, we'll use the second formula. Substitute any known values into the equation above and simplify:
2(5y – 2) = 2(5y) – 2(2)
2(5y – 2) = 10y – 4
In Step 2, the student calculated 2(5y – 2) to equal 7y – 4. However, we have just proven that 2(5y – 2) is equal to 10y – 4.
The student first made an error in Step 2, and the correct step is:
Step 2: 10y – 4 = 12 + 6y
I hope this helps!
Vary Directly: y = k*x
Vary Inversely: y = k/x
Because x and y vary directly, our equation will look like the first one.
y = k*x
With the inputted values:
-16 = k * 4
Now, to find k, isolate the variable
k = -16/4 = -4
Your final equation will then look like this:
y = -4 * x
Answer:
This may not be that accurate as I am a bit rusty with trigonometry:
tan D: d/f
sin F: f/e
tan F: f/d
cos F: d/e
sin D: d/e
cos D: f/e
