Section 2.3 Questions

Problem 2.3.12

Question

Dr. Demeo,

I'm having trouble with question #3 on Webassign, lim -> -9 (x^2+10x+9)/(x^2+8x-9) after applying rule five and then assigning each term a limit that approaches -9, I came to the equation (-9)^2+ 10(-9)+ 9/(-9)^2+ 8(-9)-9 and 0, and DNE are both answers rejected by the system. Where am I going wrong?

Thanks

Answer

For this problem, once you see that plugging -9 in for x in the denominator causes problems, your next move should be to try to factor the numerator and denominator, and see if you can cancel any like terms. (Please post again if you have more questions.)