I wasn't sure whether this belonged in this section or the algebra section. Anyway, I'm studying for the math portion of the ACT and I can't remember how to solve certain problems. Like this one:
Which of the following is NOT a factor of z^5 - 16z ?
A. z^2 - 1
B. z^2 - 4
C. z + 2
E. z - 2
Now I'm aware the answer is A but I have no idea why. If someone could provide an explanation for how to solve that would be great.
Another One: If (2x - y) / (x + y) = 2/3, then x/y = ?
(2x - y is the numerator, x + y is the denominator)
One more: For all nonzero x, y, and z such that x = yz, which of the following must be equivalent to xy?
I'm sorry if I posted in the wrong place. Thanks in advance.