Answer:
D. 2.1 + 2x = 7.5
Explanation:
The perimeter of a polygon is the sum of the lengths of all sides.
The sides here measure x, x, and y.
The perimeter of the triangle is x + x + y.
We are told the perimeter is 7.5
Now we have
x + x + y = 7.5
or
2x + y = 7.5
We are told y = 2.1, so we substitute 21.1 for y, and we get:
2x + 2.1 = 7.5
or
2.1 + 2x = 7.5
Answer: D. 2.1 + 2x = 7.5