Question

Lim x->4
x^2-9x+20/x^2-16

Answer 1

$lim_{x to 4} frac{x^2-9x+20}{x^2-16} = lim_{x to 4} frac{x-5}{x+4} = frac{-1}{8} \ frac{x^2-9x+20}{x^2-16}= frac{(x-5)(x-4)}{(x-4)(x+4)}= frac{x-5}{x+4} \x^2-9x+20=0\D=81-80=1\x_1=5\x_2=4$