To find out how much money Jacqueline will earn at her two jobs this week, we can use the expression \( 15l + 12s \).
Given:
- \( l = 5 \) (hours worked as a lab assistant)
- \( s = 7 \) (hours worked as a cashier)
Now we can substitute the values into the expression:
\[ 15l + 12s = 15(5) + 12(7) \]
Calculating each part:
- \( 15(5) = 75 \)
- \( 12(7) = 84 \)
Now combine the results:
\[ 75 + 84 = 159 \]
Thus, Jacqueline will earn $159 this week at her two jobs.