Question 186662
The limitation on picking out a common factor 
is lowest power of a symbol (x,y z, etc), or
it must be the greatest common divisor of 
the numbers that are common to each term
{{{6y^4 + 14y^3 - 10y^2}}}
The common symbols are:
{{{y^4}}}, {{{y^3}}}, and {{{y^2}}}
The lowest power is {{{2}}}, so I can 
factor out {{{y^2}}}
{{{y^2*(6y^2 + 14y - 10)}}}
For the numbers, the greatest common divisor is {{{2}}}
so I can factor out  a {{{2}}}
{{{2y^2*(3y^2 + 7y - 5)}}}