(x^2+9x)(x^2+9x+18)=68040
(x^2+9x)^2+18(x^2+9x)+81=68040+81
(x^2+9x+9)^2=261^2
x^2+9x+9=261
4x^2+36x+36+45=261*4+45
(2x+9)^2=1089
2x+9=33
x=24/2=12
55440=7*8*9*10*11
所以x=7
(x^2+9x)(x^2+9x+18)=68040
(x^2+9x)^2+18(x^2+9x)+81=68040+81
(x^2+9x+9)^2=261^2
x^2+9x+9=261
4x^2+36x+36+45=261*4+45
(2x+9)^2=1089
2x+9=33
x=24/2=12
55440=7*8*9*10*11
所以x=7