When solving an equation, Carmen's first step is shown below. Which property justifies Carmen's first step? plz help me

If there are 12 moths and some have 31 days and others have 30 days how many have 28 days?

What value of x will make the triangles similar by the sss similarity theorem?

Elena and her husband marc both drive to work. elena's car has a current mileage (total distance driven) of 15,000 and she drives 23,000 miles more each year. marc's car has a current mileage of 46,000 and he drives 9,000 miles more each year. will the mileages for the two cars ever be equal? explain.