Question

What do the brackets mean in this problem?

a[(b-c)/d]-f

Am I suppose to times the answer of everything in the parenthesis by a?

Answer 1

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[(b-c)/d]-f
is mathematically the same as
a(b-c)/d-f

But
x-3/x+2 is NOT the same as
(x-3)/(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.