
Andrew M. answered 05/01/18
Tutor
New to Wyzant
Mathematics - Algebra a Specialty / F.I.T. Grad - B.S. w/Honors
The domain is the set of all possible input values of x.
The restriction on this is that we cannot divide by zero.
Thus we must find all values of x that make the denominator zero.
Assuming we are missing the grouping parenthesis which MUST BE INCLUDED:
(2-9x)/(6x2+49x+8)
= (2-9x)/(6x2+48x+x+8)
= (2-9x)/[6x(x+8) + (x+8)]
= (2-9x)/[(6x+1)(x+8)]
Now that we have factored the denominator, look for the values that
would make that equal to zero:
6x+1=0 x+8=0
6x = -1 x = -8
x = -1/6
The domain of x is all real numbers EXCEPT -1/6 and -8
D = (-∞, -8)U(-8, -1/6)U(-1/6, ∞)