Question

SAT subject test problem:
what is the value of k if... (I will post the equation below )

Answer 1

\[\frac{ 1 }{ (x-2)(x+4) }=\frac{ h }{ (x-2) }+\frac{ k }{ (x+4) }\]

Answer 2

multiply both sides by (x-2)(x+4)

1 = h*(x+4)+k*(x-2)

subtract the h*(x+4) to the other side

1-h*(x+4) = k*(x-2)

divide both sides by x-2

(1-h*(x+4))/(x-2) = k

Answer 3

@tomo but that is not one of the answer choices.
here are the choices:
a) 2
b)-4
c)-1/6
d)1/6
e)-2

Answer 4

http://www.wolframalpha.com/input/?i=1+%3D+h*%28x%2B4%29%2Bk*%28x-2%29+for+k

Answer 5

unless you have a initial value for x and h, i don't now how to get a number for k.

Answer 6

oh, ok. Thank you