2) 2m-20 + 4 - 6 = 2m-20 + 4 - 6 =m(2m-20)+4m(m+2)-6(m-2)(m+2) =
m²-4 m-2 m (m-2)(m+2) m-2 m m(m-2)(m+2)
=2m²-20m+4m²+8m-6(m²-4)=2m²+4m²-6m²-20m+8m+24=
m(m-2)(m+2) m(m-2)(m+2)
= -12m+24 = -12(m-2) = -12
m(m-2)(m+2) m(m-2)(m+2) m(m+2)
4) 1 - x²+18 = 1 - x²+18 =x²-3x+9-x²-18 = -3x-9 =
x+3 x³+27 x+3 (x+3)(x²-3x+9) (x+3)(x²-3x+9) (x+3)(x²-3x+9)
= -3(x+3) = -3
(x+3)(x²-3x+9) x²-3x+9