Answer:
A = 3x^2 - 3
---------------
2
Explanation:
If the perimeter is 56 cm..
x - 1 + 3x + 3x + 1 = 56
7x = 56
x=8
The x - 1 side = 7
The 3x = 1 side - 25
The ex side = 24
The area of a triangle = base time height divided by 2.
So...
x-1 times 3x divided by 2 is your equation.
3x(x - 1) = 3x^2 - 3
A = 3x^2 - 3/2
Hope this is correct!!!