Answer:
Answer is b
Step-by-step explanation:
just did it
This is a combination in which you choose 4 from 10.
The formula is
combinations = 10! / 4! * (10-4)!
combinations = 10! / 4! * 6!
combinations = 10 * 9 * 8 * 7 * 6! / 4! * 6!
combinations = 10 * 9 * 8 * 7 / 4 * 3 * 2
combinations = 10 * 3 * 7
combinations = 210
Source:
http://www.1728.org/combinat.htm

Micah did not explain the last step correctly. You cannot cross out a term from the numerator and denominator unless it is a factor. In other words, x² needed to be multiplied and not added in order to cross it out.
Answer: -3x^3 - 7x^2 - x + 39
Step-by-step explanation:
2/(x^2 -9) - 3x/(x^2-5x+6)
get those denominators factored out
2/(x-3)(x+3) - 3x/(x-3)(x-2)
Multiply both by both denominators
2(x-3)(x-2) - 3x(x-3)(x+3)
Multiply it out
(2x^2 - 10x + 12) - (3x^3 + 9x^2 -9x - 27)
Simplify and it becomes
-3x^3 -7x^2 -x + 39