Plezz Help

If a + b = 9 and x + y = 1,

what is -3b - 3y - 3a - 3x?

\(\begin{array}{|lrcll|} \hline & a+b &=& 9 \\ & x+y &=& 1 \\ \text{sum} & a+b+x+y &=& 9+1 \\ & a+b+x+y &=& 10 \\\\ & && -3b - 3y - 3a - 3x \\ & &=& -3\cdot (b+y+a+x) \\ & &=& -3\cdot (a+b+x+y) \quad & | \quad a+b+x+y = 10 \\ & &=& -3\cdot (10) \\ & &=& -30 \\ \hline \end{array}\)