This is solving systems by substituting

y=-2x+5
3y=-x-5

y = - 3

Step-by-step explanation:

3(-2x+5)=-x-5

-6x+15=-x-5

-5x=-20

x=4

y=-2(4)+5

y=-3

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.

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