Question

Assinale a alternativa que indica o valor do limite
lim x -> -1 (3x²+2x -1/-x²+3x+4)
Alternativas corretas
( A) 16/25
(B) 36/25
(C) 1/16
(D) 1/25
(E) 1/4

Answer 1

Se for Lim (3x²+2x -1)/(-x²+3x+4)

          x-->-1

ax²+bx+c=a*(x-x')*(x-x'')

3x²+2x -1=0 ==>x'=-1   e  x''= 1/3

3x²+2x -1=3*(x+1)*(x-1/3) =(x+1)*(3x-1)

-x²+3x+4 = 0 ==>x'=-1   e  x''= 4

-x²+3x+4 = -1*(x+1)*(x-4) =(x+1)*(4-x)

Lim (3x²+2x -1)/(-x²+3x+4)

x-->-1

Lim (x+1)*(3x-1)/(x+1)*(4-x)

x-->-1

Lim  (3x-1)/(4-x)   =(-3-1)/(4+1) =-4/5

x-->-1