-5x + 3y = -8
3x - 7y= -3

x = 5/2   y = 3/2

Step-by-step explanation:

You need to write what the question is besides the information in the problem.  I assume the question is to find the values of x and y.

Going on that premise, Let equation (1)   be -5x + 3y = -8 and

equation (2)  be 3x - 7y = -3

Lets multiply (1) by 3 and (2) by 5 and we get equations (4) and (5)

(4)   -15x + 9y = -24    and  (5)    15x - 35y = -15  Now add (4) and (5)

-15x + 9y = -24

15x - 35y = -15

      -26y = - 39

y = 3/2     Now substitute y = 3/2 in equation (1).  -5x + 3)(3/2) = -8

                                                                                 -5x + 9/2 = -8

                                                                                  -10x + 9 = -16

                                                                                  -10x = -25

                                                                                      x = -25/-10 = 5/2  

x = 5/2   y = 3/2

Check:  Substitute your answers into equation (2) and see if they work.

3(5/2) -7(3/2) = 15/2 - 21/2 = -6/2 = -3   Hooray!  We have the correct values for x and y that makes each equation true  

54 kilometers per hour

step-by-step explanation:

according to rules:

1 km = 1000 meter

which means that 1 meter = 1/1000 km

1 hour = 3600 second [ as 1 hour = 60 min = 60 *60 seconds ]

which means that 1 second = 1/3600 hour

therefore, 1 kilometer/hour =

thus to convert 15 meter per second to kilometer per hour, we multiply 15 to 3.6 kilometer/hour.

15 meter/second=   which is the required answer.

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204