Y = -7x - 2
Use the two points given to find the slope (m)
m = (y2 - y1) / (x2 - x1)
m = ( 12-5 ) / (-2 - (-1))
m = -7
Now we have y = -7x + b where 'b' is our y-intercept. We can solve for 'b' by choosing one of the (x,y) coordinate points and plugging them in.
Let's choose the point (-1,5). Plug -1 in for 'x' and 5 in for 'y' and solve for 'b'.
y = -7x + b
5 = -7(-1) + b
b = -2
Final eqn: y = -7x - 2
Answer:
The third score must be larger than or equal to 72, and smaller than or equal 87
Step-by-step explanation:
Let's name "x" the third quiz score for which we need to find the values to get the desired average.
Recalling that average grade for three quizzes is the addition of the values on each, divided by the number of quizzes (3), we have the following expression for the average:

SInce we want this average to be in between 80 and 85, we write the following double inequality using the symbols that include equal sign since we are requested the average to be between 80 and 85 inclusive:

Now we can proceed to solve for the unknown "x" treating each inaquality at a time:

This inequality tells us that the score in the third quiz must be larger than or equal to 72.
Now we study the second inequality to find the other restriction on "x":

This ine
quality tells us that the score in the third test must be smaller than or equal to 87 to reach the goal.
Therefore to obtained the requested condition for the average, the third score must be larger than or equal to 72, and smaller than or equal 87:
One battery costs $1.44.
The unit rate would be

To get that answer, you would have to divide 13 ÷ 9.
I'm not sure if this is what you were looking for, but if it was, I hope I helped! :-)
This is the answer 7 x -3
7 x -3 = -21
Take away 1,3 it interferes with 1,1 making it not a function. You can use the vertical line test and see if more than one is in a vertical line to find it.