长沙最好的企业:一道计算题 急用

来源:百度文库 编辑:神马品牌网 时间:2024/04/29 12:01:43
(-3x-8y)(3x-8y) 要步骤

(-3x-8y)(3x-8y)
=-(3x+8y)(3x-8y)
=-(9x^2-64y^2)
=64y^2-9x^2

原式=-(3x+8y)(3x-8y)
=-(9x^2-64y^2)
=-9x^2+64y^2

(-3x-8y)(3x-8y)
=-(3x+8y)(3x-8y)
=-(9x^2-64y^2)
=-9x^2+64y^2

=-3x*3x-3x*(-8y)-8y*3x-8y*(-8y)
=-9x*x+24xy-24xy+64y*y
=64y*y-9x*x

=-(3x+8y)(3x-8y)=-[(3x+8y)(3x-8y)]=-[9*x*x-64*y*y]=64*y*y-9*x*x