To represent the number of hours, \( h \), that Tyrell still needs to volunteer to reach his goal of 26 hours, you can set up the equation:
\[ h + 17 = 26 \]
Now, to solve for \( h \), subtract 17 from both sides:
\[ h = 26 - 17 \]
Calculating the right side:
\[ h = 9 \]
So, Tyrell still needs to volunteer 9 hours to reach his goal for this month.