Can anyone me with these two questions. algebraic equation

7

3/5 (a+5.25)=7.35

3/5a+3.15=7.35

Subtract 3.15 by 3.15 which cancels it out and you do the same thing by doing 7.35- 3.15 and get 4.2

3/5a=4.2

Divide 3/5 by 3/5 which cancels it out and divide 4.2 but 3/5

Which equals 7

54 km / hours

step-by-step explanation:

we need to convert seconds to hours

60 seconds = 1 minutes

60 minutes = 1hour

15 m         60 second   60 minutes

  * *         = 54000 meters/ hour

second     1 minute             1 hour

now we need to convert meters to km

1000 m = 1 km

54000 m       1 km

*   = 54 km / hours

hour               1000m