Let $t$ be TNYWR.

If $2 t+2 x-t-3 x+4 x+2 t=30$, what is the value of $x$ ?
If $2 t+2 x-t-3 x+4 x+2 t=30$, then $3 t+3 x=30$ or $t+x=10$ and so $x=10-t$. Since the answer to (a) is 6 , then $t=6$ and so $x=10-t=4$.