Question

因式分解-5a^2+25a;25x^2-16y^2;x^3-25x;x^2(x-y)+y^2(y-x);x^2y^4-1

Answer 1

-5a^2+25a;=-5a(a-5)

25x^2-16y^2=(5x-4y)(5x+4y)

;x^3-25x;=x(x-5)(x+5)

x^2(x-y)+y^2(y-x);=x²(x-y)-y²(x-y)=(x-y)(x²-y²)=(x-y)²(x+y)

x^2y^4-16x^2;=x²(y^4-16)=x²(y²-4)(y²+4)=x²(y-2)(y+2)(y²+4)

(a+b)^2+2(a+b)+1=(a+b+1)²