1. What is the most common mistake people make when expanding brackets?
Most teachers will tell you that students forget to change all of the signs inside the bracket when expanding by a negative number. e.g. -3(x − 2) = -3x + 6 (common mistake is to put -3x - 6)
2. Is (x + 2)2 the same as 2(x + 2)?
Yes, they are the same.
Usually the number is put IN FRONT of the bracket.
3. Should I simplify expressions INSIDE the brackets first, if I can?
Yes, BEDMAS says to calculate anything inside the BRACKETS first.
e.g. 3(2x + 3x + 4 + 5) = 3(5x + 9)
Now expand to 15x + 27