Expand and simplify 23[9y−2(6x+3y)].

Sure, let's break it down:

Step 1: Distribute the 23 into the bracket:

23 * 9y - 23 * 2(6x + 3y)

Step 2: Simplify the multiplication:

207y - 46(6x + 3y)

Step 3: Distribute the 46 into the bracket:

207y - 276x - 138y

Step 4: Combine like terms:

69y - 276x

So, the simplified form of 23[9y−2(6x+3y)] is 69y - 276x.