Question 12975
Are you saying:
y = {{{(7x^2-14)/(12x^2+20) }}}

If so, the domain consists of all values of x except that the denominator must NEVER be zero.  The denominator consists of taking a value of x, squaring it, multiplying that result by 12 and then adding 20.  By looking at this you can see that squaring a number will never be negative.  Multiplying by 12 and then adding 20 will certainly always give you a positive, never a ZERO, result.  


Therefore the answer for domain is all real values, since the denominator can never be zero.


R^2 at SCC