Question

Factorise 81×^4-16y^4​

Answer 1

Answer:

(9x^2 + 4y^2)(3x+2y)(3x-2y)

Step-by-step explanation:

(9x^2)^2 - (4y^2)^2

=(9x^2 + 4y^2)(9x^2 - 4y^2)

=(9x^2 + 4y^2)[(3x)^2 - (2y)^2]

=(9x^2 + 4y^2)(3x+2y)(3x-2y)