9000=(9000/t+300)(t-1)

Solution for 9000=(9000/t+300)(t-1) equation:

D( t )

t = 0

t = 0

t = 0

t in (-oo:0) U (0:+oo)

9000 = (9000/t+300)*(t-1) // - (9000/t+300)*(t-1)

9000-((9000/t+300)*(t-1)) = 0

9000-1*(9000*t^-1+300)*(t-1) = 0

9000-1*(9000*t^-1+300)*(t-1) = 0

9000*t^-1-300*t+300 = 0

9000*t^-1-300*t+300 = 0

300*(30*t^-1-t+1) = 0

30*t^-1-1*t^1+1*t^0 = 0

(1*t^1-1*t^2+30*t^0)/(t^1) = 0 // * t^2

t^1*(1*t^1-1*t^2+30*t^0) = 0

t^1

t-t^2+30 = 0

t-t^2+30 = 0

DELTA = 1^2-(-1*4*30)

DELTA = 121

DELTA > 0

t = (121^(1/2)-1)/(-1*2) or t = (-121^(1/2)-1)/(-1*2)

t = -5 or t = 6

t in { -5, 6} 

300*(t+5)*(t-6) = 0

300*(t+5)*(t-6) = 0

( t+5 )

t+5 = 0 // - 5

t = -5

( t-6 )

t-6 = 0 // + 6

t = 6

t in { -5, 6 }