How can i solve this?

Answer:
Perimeter is (8x + 4) units.
Step-by-step explanation:
[tex]{ \sf{perimeter = side + side + side}} \\ { \sf{p = (2x + 1) + (7x - 2) + (5 - x)}} \\ { \sf{p = (2x + 7x - x) + (1 - 2 + 5)}} \\ { \sf{p = 8x + 4}}[/tex]