Help please very confused.

12.

Step-by-step explanation:

Replace k in the radical by -2:

So we have √(-72*-2)

= √144

= 12.

12

Step-by-step explanation:

The answer is B

Step-by-step explanation:

In order to write any number in scientific notation, the proper format in general for scientific notation is:

where "a" is a rational number such that its absolute value has to satisfy:

Also, "b" is the power of 10 required so that the scientific notation is mathematically equivalent to the original number.

We have to follow the next steps to determine the scientific notation of any number:

Move the decimal point in your number until there is only one non-zero digit to the left of the decimal point. The resulting decimal number is "a". Count how many places you moved the decimal point. This number is "b". If you moved the decimal to the left, "b" is positive. If you moved the decimal to the right, "b" is negative. If you did not need to move the decimal, "b" = 0.Remove trailing 0's only if they were originally to the left of the decimal point.

Finally, the number 650,000 written in scientific notation is: