Which factor do you cancel from the numerator and denominator to simplify x^2 + 3x -4 / x^2 -16?

Question

solomonzelman · Answer

$\Large\color{red}{  x^2 + 3x -4 =(x-1)(x+4)  }$
$\Large\color{blue}{  x^2 -16 =(x-4)(x+4)  }$

accidentalaichan · Answer

x - 3

accidentalaichan · Answer

That's what I guess.
x + 3 and x - 3 cancel out, so it makes sense

ʕ•ᴥ•ʔ · Answer

x+3 and x-3 don't cancel..

ipwnbunnies · Answer

(x-3)? o.o
When Solomon factored both the numerator and denominator, he factored each into two binomials. 
(x+4) is the common factor in both the numerator and denominator. That factor will cancel, and you will be left with (x-1) in the numerator and (x-4) in the denominator.

accidentalaichan · Answer

Okay x.x Thanks, Bunni ♥