Question 184194
2 is correct. The others are not. See the URLS below for tools to factor 
{{{x^3+x^2-34x+56=0}}}
{{{(x-2)(x^2 +3x -28)=0}}}
{{{(x-2)(x-4)(x+7)=0}}}

http://www.hostsrv.com/webmab/app1/MSP/quickmath/02/pageGenerate?site=quickmath&s1=algebra&s2=factor&s3=basic

http://www.calc101.com/webMathematica/long-divide.jsp#topdoit