求大神解几道初中数学题第4大题,跪求

2个回答

  • 4.(1)(-2 x+3)(-2x-3)=-(-2x+3)(2x+3)=-(-4x^2+9)=4x^2-9

    ⑵(-x/2+2y)^2=x^2/4-2xy+4y^2

    (3)-2(x/3-3y/2)^2=-2(x^2/9-xy+9y^2/4)=-2x^2/9+2xy-9y^2/2

    ⑷4(-3x/2-3y)(3x/2-3y)=-4(3x/2+3y)(3x/2-3y)=-4(9x^2/4-9y^2)=-9x^2+36y^2

    ⑸9m^2n^2-1/4-m^2n^2=8m^2n^2-1/4

    (8)(x/2+5+x/2-5)(x/2+5-x/2+5)=10x

    (7)(x+2y)^2-9z^2

    (6)x^2-(x^2-4)=4