Please help :(

Add 1/7 + -1/7 your answer should be reduced to its smallest form and should not be an improper fraction

Aregular pentagon with a perimeter of 21 inches is dilated by a scale factor of 5/3 to create a new pentagon. what is the perimeter of the new pentagon?

Point s lies between points r and t on . if rt is 10 centimeters long, what is st? 2 centimeters 4 centimeters 6 centimeters 8 centimeters