Question Number 132597 by Study last updated on 15/Feb/21
Commented by mr W last updated on 15/Feb/21
$$\frac{\mathrm{156}}{{x}+\mathrm{7}}=\frac{\mathrm{156}}{{x}}−\mathrm{14} \\ $$$$\mathrm{156}{x}=\mathrm{156}\left({x}+\mathrm{7}\right)−\mathrm{14}{x}\left({x}+\mathrm{7}\right) \\ $$$${x}^{\mathrm{2}} +\mathrm{7}{x}−\mathrm{78}=\mathrm{0} \\ $$$$\left({x}−\mathrm{6}\right)\left({x}+\mathrm{13}\right)=\mathrm{0} \\ $$$${x}=\mathrm{6},\:−\mathrm{13}\:\left({rejected}\right) \\ $$$${he}\:{expected}\:{to}\:{do}\:{the}\:{job}\:{in}\:\mathrm{6}\:{hours}. \\ $$