The first side of a triangle becomes {2a-b} cm, the second side is {a = 2B} cm longer than the first side, and the third side is less than 2 times of the first side by B. calculate the perimeter

The first side of a triangle becomes {2a-b} cm, the second side is {a = 2B} cm longer than the first side, and the third side is less than 2 times of the first side by B. calculate the perimeter

Second edge: 2a-b + A + 2B = 3A + B
Third edge: (2a-b) * 2-B = 4a-3b
The sum of three sides is (2a-b) + (3a + b) + (4a-3b) = 9a-3b

If the length of the first side of a triangle is (2a-b) cm, the second side is (a + b) cm longer than the first side, and the third side is less than 2 times of the first side by B (CM), the perimeter of the triangle is calculated (expressed by the algebraic formula of a and b)

Perimeter = (2a-b) + [(2a-b) + (a + b)] + [2 (2a-b) - b] = 2a-b + 2a-b + A + B + 4a-2b-b = 9a-4b

Let AB be the lengths of the two sides of an isosceles triangle, and m be the circumference of the triangle. What is the value of m when a B M satisfies the equations [as follows]
Equations a-2b = M-7 and a + B = m / 4 + 2