For those who don't know, here it is:

1. First Equation:
   $\text{Blue cup}+\text{Blue cup}+\text{Blue cup}=42$
   Since there are three identical blue cups, we can divide by 3:
   $\text{Blue cup}=42÷3=14$

2. Second Equation:
   $\text{Blue cup}+\text{Orange cup}+\text{Orange cup}=24$
   Substitute the blue cup value (14):
   $14+2\times \text{Orange cup}=24$
   Subtract 14 from both sides:
   $2\times \text{Orange cup}=10$
   Divide by 2:
   $\text{Orange cup}=5$

3. Third Equation:
   $\text{Orange cup}+\text{Purple cup with straw}+\text{Blue cup}=26$
   Substitute the values of the orange cup (5) and blue cup (14):
   $5+\text{Purple cup with straw}+14=26$
   Combine known values:
   $\text{Purple cup with straw}=26-19=7$

4. Final Expression:
   Now we need to solve:
   $\text{Blue cup}+\text{Purple cup with straw}-\text{Orange cup}=?$
   Substitute the values we found for each:
   $14+7-5=16$

Answer: The result is 16