px^2 + 5x 恆等 qx + r ,, p=?,,q=?,,r=??

因為 px^2 + 5x 恆等 qx + r 所以對 conefficient 就可以..

so p = 0 (對 x^2)
q = 5 (對 x)
r = 0 (對 constant)

p = [(q-5)x + r ]/ x^2

q = (px^2 + 5x - r) / x

r = px^2 + (5-q)x