What would you do to isolate the variable in the equation below, using only one step?
X + 9 = - 12
O Subtract 9 from both sides of the equation.
O Add 9 to both sides of the equation.
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O Subtract 12 from both sides of the equation.
O Add 12 to both sides of the equation.

O Subtract 9 from both sides of the equation.

Step-by-step explanation:

Notice that on the left hand side of the equation, you have two parts: X and 9. The variable is X, so we must do something to the 9 to remove it. Remember that we can cancel things by adding the negative of it. For example, 47+(-47)=0. Therefore, the opposite of 9 is -9. That essentially means subtracting 9.

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.