Wie ist der rechenweg von 4x+81=-70+x+100

4x+81=-70+x+100     | -x

3x +81 = 30                |  -81

3x  =  -51                    |  : 3

  x  =  - 17

Probe:  $${\mathtt{4}}{\mathtt{\,\times\,}}\left(-{\mathtt{17}}\right){\mathtt{\,\small\textbf+\,}}{\mathtt{81}} = {\mathtt{13}}$$            $${\mathtt{\,-\,}}{\mathtt{70}}{\mathtt{\,-\,}}\left({\mathtt{17}}\right){\mathtt{\,\small\textbf+\,}}{\mathtt{100}} = {\mathtt{13}}$$

Gruß radix !