Respuesta :
To factorize a polynomial of general form ax2+bx+c, one should divide middle term bx in two parts, whose sum is b and product is a×c.
So for x2−8x−48, we should divide −8x in two parts which add up to −8 and whose product is 1×(−48)=−48.
A few trial indicate them to be −12 and 4. Hence
x2−8x−48=x2−12x+4x−48 or
x(x−12)+4(x−12) or
(x+4)(x−12)
