1.4a²b²-(a²+b²)²
= 4a²b²-a^4-b^4-2a²b²
=-(a^2-b^2)^2
2.4(x-y)²+4(x-y)+1
=(2(x-y)+1)^2
3.(x+1)(x+2)(x+3)(x+4)+1
=
4.x³+2x²+x
=x(x^2+2x+1)
=x(x+1)^2
1.4a²b²-(a²+b²)²
= 4a²b²-a^4-b^4-2a²b²
=-(a^2-b^2)^2
2.4(x-y)²+4(x-y)+1
=(2(x-y)+1)^2
3.(x+1)(x+2)(x+3)(x+4)+1
=
4.x³+2x²+x
=x(x^2+2x+1)
=x(x+1)^2