Answer:
They say that the sum of the two numbers (x and y) is 64, so we can write our first equation by adding them and setting that sum equal to 64:
x + y = 64
The question also tells us that their difference is 14. Similarly to before, we'll just subtract the two numbers and set that difference equal to 14:
x - y = 14
Now from here, you know how to continue with substitution to find the values for x and y. Just remember when you get a word problem to break it down and look for key words like sum, difference, or product, and from there you'll be able to build your system of equations.
Simple actually. The 1000 is the starting price the -20 is the losing of value per week and the w stands for the number of weeks.
Power and chain rule (where the power rule kicks in because 
):
Simplify the leading term as
Quotient rule:
Chain rule:
Put everything together and simplify:
x=8
16-8=8
Use a calculator to find the square root of 8.
Answer:
2x - y = 9
Step-by-step explanation:
The equation of a line in standard form is
Ax + By = C ( A is a positive integer and B, C are integers )
Rearrange y + 1 = 2(x - 4) into this form
y + 1 = 2x - 8 ( add 8 to both sides )
y + 9 = 2x ( subtract y from both sides )
9 = 2x - y ⇒ 2x - y = 9 ← in standard form
