@Oluwasegun solaja I used binomial expansion to solve it

@Rose James got it first. thank you.

I will suggest we all provide detailed explanations, if we are to solve this in an examination will format will you use?

Can use adopt Pascal Triangle and teach people?

(3*2y - 4xy)(3*2y - 4xy)(3*2y - 4xy)(3*2y - 4xy)

81y^4x^8-432y^4x^7+864y^4x^6-768y^4x^5+256y^4x^4

81x^8y⁴ -432x^7y⁴+864x^6y^6-768x^5y⁴+256x⁴y⁴

(81x^8y⁴)+(108x^6y³-4xy)+(54x⁴y² +8x²y²)+(12x²y-64x³y³)+(256x¹²y⁴)