That would be a / 3b^2
(re call that 1 /a^-1 = a)
The perimeter of a triangle is the sum of all side lengths of the triangle. The numerical expression for the perimeter of Stephanie's triangle is: 
Let the sides of Juan's triangle be x, y and z. So:

The perimeter (J) of Juan's triangle is calculated by adding all sides.
So:

This gives:


From the question, we understand that:
The perimeter (S) of Stephanie's triangle is half that of Juan.
This means that:

Substitute 25 for J

Hence, the numerical expression for the perimeter of Stephanie's triangle is: 
Read more about perimeters at:
brainly.com/question/11957651
Answer:
51
Step-by-step explanation:
cos(3x) = cos(2x+x)
= cos(2x) cos (x) -sin(2x)sin(x)







