Answer
$(2x-y^2)(x-3y^2)$
Work Step by Step
The product of a binomial sum and a binomial difference is: $(A+B)(A-B)=A^2-B^2$.
The square of a binomial sum is: $(A+B)^2=A^2+2AB+B^2$.
The square of a binomial difference is: $(A-B)^2=A^2-2AB+B^2$.
Hence here: $2x^2-7xy^2+3y^4=\\=2x^2-xy^2-6xy^2+3y^4\\=x(2x-y^2)-3y^2(2x-y^2)\\=(2x-y^2)(x-3y^2)$