Quickk experts/ace or anyone who wants to

1. during first 10 seconds 2. between 10 seconds and 35 seconds 3. during 35 seconds to 40 seconds

Two times a number plus three times another number equals 4. three times the first number plus four times the other number is 7. find the numbers

Sanjay solved the equation below. which property did he use to determine that 7x+42=42 is equivalent to 7(x+6)=42 7x+42=42 7x=0 x=0