math
posted by joe .
how do i solve by factoring x^4+2x^2y^2+9y^4

change x^2 = u, and y^2=z
u^2+2uz+9z^2 which is (u+z)^2
posted by joe .
how do i solve by factoring x^4+2x^2y^2+9y^4
change x^2 = u, and y^2=z
u^2+2uz+9z^2 which is (u+z)^2