To find the product of 6x and [4-21 730], we need to simplify the expression first.
To simplify, we perform the subtraction first and then multiply.
So, [4-21 730] can be simplified as follows: [4-21 730] = 4 - 21730 = -21726
Now, we can find the product of 6x and -21726 as follows: 6x(-21726) = -130356
Therefore, the product of 6x and [4-21 730] is -130356.