Please help i'll give brainilist if its correct

Answer:
7x+2x
Step-by-step explanation:
hope thats right only did it for one week
Answer:
3x + 7
Step-by-step explanation:
The perimeter of a triangle is the sum of all of its side lengths. In this case, we know all of its side lengths. x + 7 + 2x. Simplify by combining like terms. 3x + 7 is the answer.