几道分解因式的题目，很简单，急求

4x^2-y^2=(2x+y)(2x-y)
x^2+x+1/4=(x+1/2)^2
4a^7-a^5= a^5(2a+1)(2a-1)
3a(m-n)+2b(n-m)= (3a-2b)(m-n)
4mx^2-8m^2x+4m^3=4m(x-m)^2
x^3y-xy^3= xy(x+y)(x-y)

因式分解，需过程。
2x-7-1/7x^2=-(x^2-14x+49)/7=-(x-7)^2/7
x^4-16= (x^2+4)(x+2)(x-2)
(x-2y)^2-14(x-2y)+49= (x-2y-7)^2
(x-y)^3+4(y-x)=(x-y)(x-y+2)(x-y-2)
(x1+x2)^2-4x1x2=(x1-x2)^2

4x^2-y^2= (2x+y)(2x-y)
x^2+x+1/4= (x+1/2)^2
4a^7-a^5= a^5(4a^2-1)=a^5(2a+1)(2a-1)
3a(m-n)+2b(n-m)= (m-n)(3a-2b)
4mx^2-8m^2x+4m^3= 4m(x^2-2mx+m^2)=4m(x-m)^2
x^3y-xy^3= xy(x+y)(x-y)

因式分解，需过程。
2x-7-1/7x^2= -1/7(x^2-14x+49)=-1/7(x-7)^2
x^4-16= (x^2+4)(x^2-4)=(x^2+4)(x+2)(x-2)
(x-2y)^2-14(x-2y)+49= (x-2y-7)^2
(x-y)^3+4(y-x)= (x-y)(x-y+2)(x-y-2)
(x1+x2)^2-4x1-x2=

做是会做，可是一个一个打出来就有点.........