Answer:
The correct option is 3.
Explanation:
It is given that the length of sides of a triangle are 0.5x+9, 3x, and -3.4x-25.
Let a=0.5x+9, b=3x, and c=-3.4x-25.
Perimeter of a triangle is the sum of length of all three sides.

Substitute a=0.5x+9, b=3x, and c=-3.4x-25 in the above equation.

On simplification, we get

Combine like terms.



Perimeter of the triangle is 0.1x-16. Therefore the correct option is 3.