1.x的五次方-x三次方y-12xy的四次方 2.x的三次方-8y三次方-x²-2xy-4y平方 3.(2a+b)三次方-b三次方 4.-1/2n²+2m² 5.4x²-56x-1829
快速一点 万分感谢
x^5-x^3y-12xy^4=x(x^4-x^2y-12y^4) 提取公因式
x^3-8y^3-x^2-2xy-4y^2= (x^3-8y^3)-(x^2+2xy+4y^2)
=(x-2y)(x^2+2xy+4y^2)-(x^2+2xy+4y^2) = (x^2+2xy+4y^2)(x-2y-1)
分组,立方差公式
(2a+b)^3-b^3=8a^3+12a^2b+6ab^2=2a(4a^2+6ab+3b^2)
-(1/2)n^2+2m^2=(1/2)(4m^2-n^2)=(1/2)(2m+n)(2m-n)
4x^2-56x-1829=(2x+31)(2x-59).