Question 302148
	f(x) =  5x + 21/x  ; f(x) = -38 

-38 = 5x + (21/x)
-38x = 5x^2 + 21
5x^2 + 38x + 21 = 0
(5x + 3)(x + 7) = 0 

Therefore,
5x+3 = 0 
x = -3/5

or 
x+7 = 0
x=-7

Answer: x = -3/5 and -7