Verhältnisse und Proportionen https://www.mathematische-basteleien.de/verhaeltnis.htm
(a+b):b = (c+d):d a:(a+b) = c:(c+d) (a-b):b = (c-d):d a:(a-b) = c:(c-d
(a+b):b = (c+d):d a:(a+b) = c:(c+d) (a-b):b = (c-d):d a:(a-b) = c:(c-d
f(x)=ax²+bx+c (allgemeine Form) <=> f(x)=a[x²+(b/a)x]+c <=> f(x)=a{x²+(b/a)x