The graph below shows the number of paintballs a machine launches, y, in x seconds:

a graph titled rate of launch is shown. the x axis label is time in seconds, and the x axis values are from 0 to 20 in increments of 4 for each grid line. the y axis label is number of balls, and the y axis values from 0 to 100 in increments of 20 for each grid line. a line is shown connecting points on ordered pair 4, 20 and 8, 40 and 12, 60 and 16, 80.

which expression can be used to calculate the rate per second at which the machine launches the balls?

fraction 80 over 4

fraction 20 over 4

fraction 4 over 80

fraction 4 over 20

The expression that can be used to calculate the rate per second at which the machine launches the balls is fraction 20 over 4.

Step-by-step explanation:

The x-axis label is Time in seconds, and the x-axis values are from 0 to 20 in increments of 4 for each grid line.

And the y-axis label is Number of Balls and the y-axis values from 0 to 100 in increments of 20 for each grid line.

If the ordered pairs (4,20) and (8,40) are on the graph, then the slope of the line will be represented by  

Therefore, the expression that can be used to calculate the rate per second at which the machine launches the balls is fraction 20 over 4. (Answer)

the equation cos(35) =a/25 can be used to find the length of bc what is the length of bc? round to the nearest tenth

step-by-step explanation:

let's cover over the formula of the vertex:

y = a(x – h)^2 + k

in this formula, (h,k) are the vertex, always remember that the positive or negative value of the vertex is based on the sign it has.

for example, if the vertex is -3,-6 then both the x and y value would have the positive sign attached to it and if it were a positive x and y value, then a negative sign would be attached to it.

with that being said, for our problem the x value is a positive one so we are looking for a number with a negative sign next to it, in this case the first and second choice.

however, for the first answer choice it isn't quite part of the formula so we know that the answer choice correctly displays the x value.

to confirm, we can see if the -1 fits correctly with the second answer choice, and as mentioned above a negative number will have a positive sign attached to it. so, for our problem we can see that -1 has been changed to +1, so we can confirm that the second answer choice is correct.

hence, our final answer is y=(x - 1)^2 + 1