Question

|3x-6| less than or equal too 21

Answer 1

Less than what is 6x3?=18

Answer 2

It is less than 21

Answer 3

I'll write "<=" to mean less than or equal to.
|3x-6| <= 21 is the same as:
-21 <= 3x - 6 <= 21, this is one of the rules of absolute value.
Then you just have to solve for x, so add 6 to each side first:

-21 + 6 <= 3x - 6 + 6 <= 32 + 6
-15 <= 3x <= 9
Divide by 3 to isolate the x,
-5 <= x <= 9

So the solution to |3x-6| <= 21 is -5 <= x <= 9.

Answer 4

Sorry about that typo in there --> the 32 should be 21:

so when you're adding the 6:
-21 + 6 <= 3x - 6 + 6 <= 21 + 6
-15 <= 3x <= 27

Then the rest is as I posted earlier.