Question

let us factorise
81x4 ± 4y2 ​

Answer 1

Answer:

$4{y}^{2} = 81 \times 4 \\ \\ {y}^{2} = 81 \\ \\ y = ±9$

Answer 2

Answer:

$81 \times 4 + 4 {y}^{2} \\ \\ = 4 {y}^{2} + 324 = 4( {y}^{2} + 81)$