Because 5(1.50) is equal to 7.50 and they subtract it from both sides so that they can be left with the stapler and how much was spent on the stapler. You can replace d+7.50-7.50 with d because 7.50-7.50 is equal to zero
3.412×10^1
Hope this helps and have a good day!
Answer:
Step-by-step explanation:
I'm just as confused