When solving this system of equations using linear combination, what should you do first? -x+y=-1
2x+y=19

Multiply the first equation by 2

Add the two equations together

solve the first equation for y

multiply the first equation by 1

54 km / hours

step-by-step explanation:

we need to convert seconds to hours

60 seconds = 1 minutes

60 minutes = 1hour

15 m         60 second   60 minutes

  * *         = 54000 meters/ hour

second     1 minute             1 hour

now we need to convert meters to km

1000 m = 1 km

54000 m       1 km

*   = 54 km / hours

hour               1000m

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step-by-step explanation:

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step-by-step explanation:

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