So just plug in the numbers (x,y) into the equations.
A) (7.5, -5)
2(7.5) -5 = 10
15 - 5 = 10 yup, this works.
Let's see if it works for other equation.
-2(7.5) + 2(-5) = 5
-15 - 10 = 5 nope, this does not work.
B) (-2.5, -5)
2(-2.5) - 5 = 10
-5 - 5 = 10 nope, doesn't work
Since it doesn't work we don't need to try for other equation.
C) (2.5, 5)
2(2.5) + 5 = 10
5 + 5 = 10 yup, this works.
Now the other equation.
-2(2.5) + 2(5) = 5
-5 + 10 = 5 and this works.
So the solution to this set is answer choice C
The colored sheets of paper will cost $1.25 and the package of stickers will cost $3.75. Together before sales tax her total is $5.00.
To answer this item, we let x and y be the rate of the boat in still water and current, respectively. The distance traveled by the object is equal to the product of the speed and the time.
Upstream:
D = (x + y)(6)
24 = 6x + 6y
4 = x + y
Downstream:
D = (x - y)(6)
18 = 6x - 6y
3 = x - y
The values of x and y are 3.5km/h and 0.5 km/h, respectively.
Answers:
Rate in Still water = 3.5 km/h
Rate of the current = 0.5 km/h
Answer: before i can answer i need the image

The denominator of a fraction can't be equal to 0.

The function is undefined at x=-1, x=2, x=4, because for these values the denominator of the function would equal 0, and it's impossible to divide by 0.
Edward is correct.