Question 1067762
<pre>
{{{12x^3-20x^2-8x}}}

Factor out 4x

{{{4x(3x^2-5x-2)}}}

Multiply 3 times -2, get -6
Think of two integers that when multiplied give -6,
yet when combined give -5.  If you think hard enough,
you'll come up with -6 and +1, because when multiplied
they give -6 and when combined they give -5.  So write
-5x as -6x+1x

{{{4x(3x^2-6x+1x-2)}}}

Factor 3x out of the first two terms inside the parentheses:

{{{4x(3x(x-2)^""+1x-2)}}}

Factor +1 out of the last two terms inside the parentheses: 

{{{4x(3x(x-2)^""+1(x-2)^"")}}}

Factor (x-2) out of both terms in the big parentheses:

{{{4x((x-2)(3x+1)^"")}}}

Drop the big parentheses:

{{{4x(x-2)(3x+1)}}}

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{{{42x^2-23x-5}}}

Try breaking up 42x² as 6x time 7x

{{{(matrix(1,3,6x,"",""))(matrix(1,3,7x,"",""))}}}

Ignoring the sign of -5, try breaking up 5 as 5 times 1 or as 1 times 5

{{{(matrix(1,3,6x,"",5))(matrix(1,3,7x,"",1))}}} or {{{(matrix(1,3,6x,"",1))(matrix(1,3,7x,"",5))}}}

There is no way to put signs in to make FOIL word, but
there is for the second one.

{{{(matrix(1,3,6x,""+"",1))(matrix(1,3,7x,""-"",5))}}}

Now you check by multiplying them out using FOIL or distributing.

Edwin</pre>