Let's expand and simplify the expression:
5/6(4,8x^2 - 30y) - 3x(x + 5y) + 15= 5/6 4.8x^2 - 5/6 30y - 3x^2 - 3x * 5y + 15= 4x^2 - 25y - 3x^2 - 15xy + 15= x^2 - 15xy - 10y
So, the simplified expression is x^2 - 15xy - 10y.
Let's expand and simplify the expression:
5/6(4,8x^2 - 30y) - 3x(x + 5y) + 15
= 5/6 4.8x^2 - 5/6 30y - 3x^2 - 3x * 5y + 15
= 4x^2 - 25y - 3x^2 - 15xy + 15
= x^2 - 15xy - 10y
So, the simplified expression is x^2 - 15xy - 10y.