To find out how much Sandra would have in her bank account after 14 weeks, we can evaluate the function \( f(x) = 25x + 150 \) at \( x = 14 \).
Substituting \( 14 \) for \( x \):
\[ f(14) = 25(14) + 150 \]
Calculating \( 25 \times 14 \):
\[ 25 \times 14 = 350 \]
Now, adding \( 150 \):
\[ f(14) = 350 + 150 = 500 \]
Therefore, after 14 weeks, Sandra would have $500 in her bank account.