Hello!
26xy(x + 5)(y - 4) ÷ 13x(y - 4) =
= 2xy × (x + 5) × (y - 4)x × (y - 4) =
= 2x²y × (x + 5) × (y - 4) × (y - 4) =
= 2x²y × (x + 5) × (y - 4)² =
= 2 × [x × (y - 4)]² × y × (x + 5) =
= 2(xy - 4x)² × y × (x + 5) =
= (2xy + 10y) × (x²y² - 8x²y + 16x²) =
= 2x³y³ - 16x³y² + 32x³y + 10x²y³ - 80x²y² + 160x²y
Good luck! :)