问几道七年级数学题(有过程)能做几道做几道,但要正确
问题描述:
问几道七年级数学题(有过程)能做几道做几道,但要正确
(x-1)^3+(x-2)^3+(2x-3)^3
(x+1)^4+(x^2-1)^2+(x-1)^4
(x+y)^4+x^4+y^4
x^4+2x^3+4x^2+2x+3
x^3-3px^2+(3p^2-q^2)x-p(p^2-q^2)
(xy+1)(x+1)(y+1)+xy
(x^3+y^3)^2-4xy[x^4+x^2y^2+y^4-2xy(x^2-xy+y^2)]
x^3(a+1)-xy(x-y)(a-b)+y^3(b+1)
(ab+cd)(a^2-b^2+c^2-d^2)+(ac+bd)(a^2+b^2-c^2-d^2)
xyz(x^3+y^3+z^3)-x^3y^3-y^3z^3-z^3x^3
已知x+y-2是多项式x^2+axy+by^2-5x+y+6的一个因式,求a、b的值并分解因式
^2是2次方,^3是3次方
答
(x-1)^3+(x-2)^3+(2x-3)^3 =(x^3-3x^2+3x-1)+(x^3-6x^2+12x-8)+(8x^3-36x^2+54x-27)=10x^3-45x^2+69x-36(x+1)^4+(x^2-1)^2+(x-1)^4 =(x+1)^2*(x+1)^2+(x^2-1)^2+(x-1)^2*(x-1)^2=(x^4+4x^3+6x^2+4x+1)+(x^4-2x^2+1...