$-\frac{ 3 }{ 2 }-\frac{ 1 }{ 3 } \times \left( -4.5+6y \right)$
Convert the decimal into a fraction$-\frac{ 3 }{ 2 }-\frac{ 1 }{ 3 } \times \left( -\frac{ 9 }{ 2 }+6y \right)$
Distribute $-\frac{ 1 }{ 3 }$ through the parentheses$-\frac{ 3 }{ 2 }+\frac{ 3 }{ 2 }-2y$
Since two opposites add up to $0$, remove them from the expression$-2y$