Verified answer

x³ - 4x = x(x²-4) = x (x+2)(x-2)

2x² -6x -20 = 2(x² -3x -10) = 2(x+5) .(x-2)

x(x+2) . (x-2) / 2(x+5) . (x-2) = x(x+2) / 2(x+5)

x³-4x/2x²-6x-20=

x(x²-4)/x²-3x-10=

x(x+2)(x-2)/(x-5)(x+2)=

x(x-2)/(x-5)

x³-4x = x(x+2)(x-2)

2x²-6x-20 = 2(x²-3x-0) = 2(x-5)(x+2)

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