Step-by-step explanation
The perimeter of a polygon is given by the sum of the length of its sides. For the polygon in the picture we have the following side lengths:

Then their sum is:

We can group like terms. Like terms are terms multiplied by the same power of x. In this case we have two groups of like terms: constants and terms multiplied by x. Then we group them:

We can use the distributive property in the terms with x. For example:

We use this and we also add the constants so we get:

Answer
Then the answer is that the perimeter of the figure is 18x+44.