(m²+8m-9)/(m²+12m+27)
m²+8m-9=0 D=100 m₁=1 m₂=-9 (m-1)(m+9)=0
m²+12m+27=0 D=36 m₁=-3 m₂=-9 (m+3)(m+9)=0 ⇒
(m-1)(m+9)/((m+3)(m+9))=(m-1)/(m+3).
(2x²+9x-18)/(4x²-9)
2x²+9x-18=0 D=225 x₁=-6 x₂=1,5 2(x+6)(x-1,5)=0
2(x+6)(x-1,5)/((2x-3)(2x+3))=(x+6)(2x-3)/((2x-3)(2x+3))=(x+6)/(2x+3).