

a/ [tex]4x^2-(x^2+1)^2[/tex]
b/ [tex]9(2x-3)^2-4(x+1)^2[/tex]
c/ [tex](x^2+xy)^2-(y^2+xy)^2[/tex]
d/ [tex](x^2+4y^2-20)^2-16(xy-4)^2[/tex]
e/ [tex]25(x-y)^2-16(x+y)^2[/tex]
help me help me
b/ [tex]9(2x-3)^2-4(x+1)^2[/tex]
c/ [tex](x^2+xy)^2-(y^2+xy)^2[/tex]
d/ [tex](x^2+4y^2-20)^2-16(xy-4)^2[/tex]
e/ [tex]25(x-y)^2-16(x+y)^2[/tex]
help me help me