a: Sửa đề: \(4x^4+3x^2y^2+y^4\)
\(=4x^4+4x^2y^2+y^4-x^2y^2\)
\(=\left(2x^2+y^2\right)^2-\left(xy\right)^2\)
\(=\left(2x^2-xy+y^2\right)\left(2x^2+xy+y^2\right)\)
b: \(=\left(x^2+10x+16\right)\left(x^2+10x+24\right)+16\)
\(=\left(x^2+10x\right)^2+40\cdot\left(x^2+10x\right)+400\)
\(=\left(x^2+10x+20\right)^2\)