12/y=10-1y

Solution for 12/y=10-1y equation:

D( y )

y = 0

y = 0

y = 0

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

12/y = 10-(1*y) // - 10-(1*y)

1*y+12/y-10 = 0

y+12/y-10 = 0

1*y^1+12*y^-1-10*y^0 = 0

(1*y^2-10*y^1+12*y^0)/(y^1) = 0 // * y^2

y^1*(1*y^2-10*y^1+12*y^0) = 0

y^1

y^2-10*y+12 = 0

y^2-10*y+12 = 0

DELTA = (-10)^2-(1*4*12)

DELTA = 52

DELTA > 0

y = (52^(1/2)+10)/(1*2) or y = (10-52^(1/2))/(1*2)

y = (2*13^(1/2)+10)/2 or y = (10-2*13^(1/2))/2

y in { (10-2*13^(1/2))/2, (2*13^(1/2)+10)/2} 

y in { (10-2*13^(1/2))/2, (2*13^(1/2)+10)/2 }