Question

-16x^4+81y^4 （四次方的意思是x^4,而不是-16x这个整体的四次方,y^4也是同样

Answer 1

解

-16x^4+81y^4

=(9y^2)^2-(4x^2)^2

=(9y^2-4x^2)(9y^2+4x^2)

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

2x^2+2x+1/2

=1/2(4x^2+4x+1)

=1/2(2x+1)^2