Simple Polynomials?

向上移動2a-3線條與a-2線條連接

Lx = (a-2) + (2a-3) = 3a - 5


同樣的方法: 中間線條向右移動與右側線條連接

形成一ㄍ長方形 它的周圍長度不變

P(a) = 2*(Lx + Ly)

= 2*[(3a-5) + (3a+1)]

= 2*(6a-4)

= 4*(3a-2)

P(3) = 4*(9-2) = 28