How does x^2(4.72*10^-12)-x(3.26*10^-6)-1=0 become x= .920072? If you know how can you show me the steps to the answer.

It doesn't

x = [(3.26*10^-6)±√((3.26*10^-6)^2+4*4.72*10^-12)]/(2*4.72*10^-12)
= [(3.26*10^-6)±√(10.6276*10^-12+18.88*10^-12)]/(2*4.72*10^-12)
= [(3.26*10^-6)±√(29.5076*10^-12)]/(9.44*10^-12)
= [3.26*10^-6 ± 5.432*10^-6]/(9.44*10^-12)
= 920772 for the larger root