d) (x2y – 3xy2 – y2) + (5xy2 – 4y2 + 5x2y).

d) (x²y – 3xy² – y²) + (5xy² – 4y² + 5x²y)

= x²y – 3xy² – y² + 5xy² – 4y² + 5x²y

= (x²y+ 5x²y) + (– 3xy²+ 5xy²) +(– y²– 4y²)

= 6x²y + 2xy²– 5y².