Add. Your answer should be an expanded polynomial in standard form. (- 4b ^ 2 + 8b) + (- 4b ^ 3 + 5b ^ 2 - 8b) =

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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step-by-step explanation:

1k

step-by-step explanation:

-6k+7k

(-6+7)k

1k