Rectangle p’r’s’t is a dilation of rectangle prst and scale factor is 3. write an equation for the perimeter of p’r’s’t if the original sides of the rectangle were x and y

The perimeter formula for the original PRST rectangle is:
 P = 2x + 2y
 To find the perimeter formula of the rectangle P'R'S'T we must use the scale factor and substitute in each dimension.
 We have then:
 P '= 2 (3x) +2 (3y)
 Rewriting:
 P '= 6x + 6y
 P '= 6 (x + y)
 
 An equation for the perimeter of P'R'S'T is:
 P '= 6 (x + y)

Basic algebra equation. first set up your equation: divide out 9.and now you are left with 2x + 4 = 8.