12.9 = x + 7.1
subtract 7.1 from both sides to isolate the variable, x.
5.8 = x
5.8 is your answer.
Lennon used the property o addition
They would make 2,000 because 150X10=1,500+500

as you notice above, is the first-row components from A, multiplying all the columns subsequently on B, and you add the products of that row, that gives you one component on the AB matrix
in the one above, we end up with a 2x3 AB matrix
11 mins
5:00
5:12
5:24
5:36
5:48
6:00
so the minutes go up in 12s meaning that their will be a bus at 7 and 8 so then you can work out
8:00
8:12
8:24
8:36
8:48
and 8:48 - 8:37 = 11 minutes waiting time