Most students know the distributive property:
a(b + c) = ab + ac
Here’s an example that involves distributing, however, that I’ve seen many students mess up.
The wrong way:
(x + 3) - (3x + 4) = x + 3 - 3x + 4 = -2x + 7
The right way:
(x + 3) - (3x + 4) = x + 3 - 3x - 4 = -2x - 1
For some reason, when there is a negative outside the parenthesis, many students (under the pressure of a timed test) forget to distribute the negative. If you stay conscious of this common pitfall, you are sure to avoid an “avoidable” error on the SAT. Good luck!