因式分解
13x^2y+28y^2+7xy^2+12xy
2a^4-3a^2-4
36x^2-17x-10
46(m-n)^2-10m+10n-4
5x^3-2x^2y+xy^2-x
6x^3+xy-2y^2
73y^n-1-6y^n-2-9y^n-3
8若三角形ABC的三边a、b、c满足a^4-b^2c^2+a^2c^2-b^4=0则三角形ABC是——