Answer
$$
\frac{ Q+WCT_2}{WC}\ , \ 94
.$$
Work Step by Step
To solve the given equation for $T_1$, we move out the term $WCT_2$ and then we divide both sides by $WC$ as follows
$$
Q= WC(T_1-T_2) \Longrightarrow Q=WCT_1-WCT_2 \Longrightarrow WCT_1=Q+WCT_2\Longrightarrow T_1=\frac{ Q+WCT_2}{WC}
.$$
Now, by substitution, we have
$$
T_1=\frac{ Q+WCT_2}{WC}=\frac{ 18.9+3\times0.18\times59}{3\times0.18}=94
.$$
