Answer:
7.5 cm²
Step-by-step explanation:
Dimensions of the large ∆:


Dimensions of the small ∆:


Difference between the area of the large and the small ∆ = 13.5 - 6 = 7.5 cm²
Answer: The last line is a mistake
Step-by-step explanation: because you are not supposed to combine something that has a term and something that doesn't. So it should just stay has 40g+24