dY=-b2/(1-c1-b1)*1/k2*(-dM/P+k1dY) | hintere Klammer ausmultiplizieren
dY=-b2/(1-c1-b1)*1/k2*(-dM/P) -b2/(1-c1-b1)*1/k2*(k1dY) | + b2/(1-c1-b1)*1/k2*(k1dY)
dY +b2/(1-c1-b1)*1/k2*(k1dY) = -b2/(1-c1-b1)*1/k2*(-dM/P) | links dy ausklammern
dY (1 + b2/(1-c1-b1)*1/k2*k1) = -b2/(1-c1-b1)*1/k2*(-dM/P)