To simplify the expression \( 5(y + 3x) - 4(x - 3y) \), follow these steps:
Distribute \( 5 \) in the first part: \[ 5(y + 3x) = 5y + 15x \]
Distribute \( -4 \) in the second part: \[ -4(x - 3y) = -4x + 12y \]
Now combine both results: \[ 5y + 15x - 4x + 12y \]
Combine like terms:
- For \( x \) terms: \( 15x - 4x = 11x \)
- For \( y \) terms: \( 5y + 12y = 17y \)
The simplified expression is: \[ 11x + 17y \]
Thus, the final result is: \[ 11x + 17y \]