1)x^2+6x+8
x^2+4x+2x+8
x*(x+4)+2(x+4)
(x+2)*(x-4)
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2)m^2-7mn+12n^2
m^2-6mn+9n^2-mn+3n^2
(m-3n)^2-n(m-3n)
(m-3n)*(m-3n-n)
(m-3n)(m-4n)
------------------------
3)a^2-7ab+10b^2
a²-(2ab+5ab)+10b²
a²-2ab-5ab+10b²
a(a-2b)-5b(a-2b)
(a-2b)(a-5b)
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