I think the question here is to clean up this expression and simplify it.
-- Eliminate the first set of parentheses:
3 (8z - 1) = 24z - 3
-- Eliminate the second set of parentheses:
-6 (5 + 3z) = -30 - 18z
-- Now write the whole thing without the parentheses:
24z - 3 + 10 - 30 - 18z
-- Add up all the z's:
24z - 18z = 6z
-- Add up all the plain old numbers:
-3 + 10 - 30 = -23
-- Write the z's and plain old numbers together:
6z - 23
And that's exactly the same thing as the whole ugly mess
that we started out with in the question.
