Answer:
10x² + 8x + 22
Explanation:
The perimeter of a rectangle is the measurements of all four side lengths added together
(you can simply multiply both side lengths by 2, because they are the same on both sides--but I'll write them all out for clarity)
side A (top): 5x² + 3x + 7
side B (right): x + 4
side C (bottom): 5x² + 3x + 7
side D (left): x + 4
perimeter = side A + side B + side C + side D
5x² + 3x + 7 + x + 4 + 5x² + 3x + 7 + x + 4
now, as you might have noticed, this is a long equation
so, we must combine like terms:
(this is the problem reordered so like terms are next to each other:)
(5x² + 5x²) + (3x + x + 3x + x) + (7 + 4 + 7 + 4)
10x² + 8x + 22
So, the perimeter of this rectangle is 10x² + 8x + 22
hope this helps! have a lovely day :)