81x^4 − 16 July 8, 2019 16 32 64 128 81x 4 16 81x 4 16 0 81x 4 16 factored 81x 4 16y 8 81x 4 16y 4 81x 4 16y 4 factored completely 81x 4 72x 2 16 Factorise 81x 4 16y 4 81x 4 16y 4 3 4