5*(5*4!*(X+2)!-5*2*4!*(X+1)!)=36*(X!*5!*2),

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  • 5*(5*4!*(X+2)!-5*2*4!*(X+1)!)=36*(X!*5!*2)

    5*(5!*(X+2)!-2*5!*(X+1)!)=36*(X!*5!*2)

    5*((X+2)!-2*(X+1)!)=36*(X!*2)

    5*(X+2)!-10*(X+1)!)=72*X!

    5*(X+2)*(X+1)*X!-10*(X+1)*X!=72*X!

    5*(X+2)*(X+1)-10*(X+1)=72

    5*(X+2)*(X+1)-10*(X+1)-72=0

    5(X+2)(x+1)-10(X+1))-72=0

    解得:

    x=