648000/y-20y=3000

Solution for 648000/y-20y=3000 equation:

D( y )

y = 0

y = 0

y = 0

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

648000/y-(20*y) = 3000 // - 3000

648000/y-(20*y)-3000 = 0

648000/y-20*y-3000 = 0

648000*y^-1-20*y^1-3000*y^0 = 0

(648000*y^0-20*y^2-3000*y^1)/(y^1) = 0 // * y^2

y^1*(648000*y^0-20*y^2-3000*y^1) = 0

y^1

648000-20*y^2-3000*y = 0

648000-20*y^2-3000*y = 0

DELTA = (-3000)^2-(-20*4*648000)

DELTA = 60840000

DELTA > 0

y = (60840000^(1/2)+3000)/(-20*2) or y = (3000-60840000^(1/2))/(-20*2)

y = -270 or y = 120

y in { -270, 120} 

y in { -270, 120 }