Math
posted by Karen .
What do the brackets mean in this problem?
a[(bc)/d]f
Am I suppose to times the answer of everything in the parenthesis by a?

The brackets [] are superfluous if the formula is entered into an algebraic calculator or if calculated by someone who follows the rules of algebraic priorities (x and ÷ before + and ), and from left to right for operators of the same priority.
So
a[(bc)/d]f
is mathematically the same as
a(bc)/df
But
x3/x+2 is NOT the same as
(x3)/(x+2)
In the second expression, the parentheses () force the subtraction and addition to be performed before the division. Without the parentheses, the mathematical meaning of the expression is then
x  (3/x) + 2
which is completely different.