计算括号3a加上b减去2乘以括号3a减去b加2

1个回答

(3a+b-2)(3a-b+2)
=[3a+(b-2)][3a-(b-2)]
=9a^2-(b-2)^2
=9a^2-(b^2-4b+4)
=9a^2-b^2+4b-4