Dear Sir or Madam;
Thank you in advance
Dennis Dyer (Father)Hi Dennis,
To simplify the expression 21+2[3z+5(3z+8)] you need to approach it from "the inside out". This expression has parentheses, ( ), nested "inside" square brackets, [ ], so working from the "inside out" start with (3z+8).
Thus the expression inside the square brackets becomes
Now working your way outside the square brackets
The last step is to add 21 to get
This has much more detail then I would include as a solution. If asked to simplify 21+2[3z+5(3z+8)] my solution would be: