SOLUTION: let f(x) = 5/(b+5) - 2/b. Find the domain and simplify.

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Question 777731: let f(x) = 5/(b+5) - 2/b. Find the domain and simplify.
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Assuming you mean x instead of b

f(x) = 5/(x+5) - 2/x

f(x) = 5x/(x(x+5)) - 2/x

f(x) = 5x/(x(x+5)) - 2(x+5)/(x(x+5))

f(x) = (5x - 2(x+5))/(x(x+5))

f(x) = (5x - 2x - 10)/(x(x+5))

f(x) = (3x - 10)/(x(x+5))

To find the domain, set the denominator equal to zero and solve for x to find the values that aren't allowed

x(x+5) = 0 ---> x = 0 or x = -5

so the domain is the set of all real numbers but x cannot equal 0 and x cannot -5