# limits problem solving help!!!!

• Dec 7th 2008, 10:08 PM
Kuma
limits problem solving help!!!!
Alrighty so i have no idea where to even start...

Find the constant c such that

Lim
x-> 3

x^2+x+c
-----------
X^2 - 5x + 6

exists

Yeah so

so far i got as far as factoring the bottom

(x-3)(x-2)

And now i have no idea where to go from there
any ideas?
• Dec 7th 2008, 10:20 PM
nzmathman
You need to get rid of the (x-3) on the bottom for this to work.

You have $\frac{x^2 + x + c}{(x - 3)(x - 2)}$

The only way to keep $x^2 + x$ in the top part is to have the factors $(x - 3)(x + 4)$.

Which means c = -12.

You get limit as x tends to 3 of $\frac{x+4}{x-2} = 7$