To find out how much Ms. Tanaka will earn for selling 12 televisions, you can substitute \( t = 12 \) into the equation:
\[ \text{Earnings} = 2,500 + 100t \]
Now substituting \( t = 12 \):
\[ \text{Earnings} = 2,500 + 100 \times 12 \]
Calculating \( 100 \times 12 \):
\[ 100 \times 12 = 1,200 \]
Now adding that to her base salary:
\[ \text{Earnings} = 2,500 + 1,200 = 3,700 \]
So, Ms. Tanaka will earn $3,700 for selling 12 televisions this month.