Three numbers have a mean of 12 and a mode of 9. What are the three numbers?

The three numbers are : 9, 9 and 18

Step-by-step explanation:

Since the mean is 12 the sum of the three numbers must be 36. This is because:

(let the three numbers be x y and z)

(x+y+z)/3=12

(x+y+z)=12*3

(x+y+z)=36

And since the mode is 9 two of the numbers must be 9.

So to find the third number;

9+9+z=36

z=36-18

z=18

x=-2

infinite number of lines, so there is an infinite number of equations.

step-by-step explanation:

there are an infinite number of line that passes through the point (-2,5)

x=-2   is one line that passes through the point

y = 5 is another line that passes through the point

(these two lines are perpendicular to each other).

since the number of   numbers are infinite and the slope is the ratio of two numbers,(change in y over change in x) we can have an infinite number of slopes.     our only condition is that it passes through the point (-2,5)

reduce the friction between its moving parts

step-by-step explanation:

in fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.