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x in (-oo:+oo)
R = (x*(2200-(3*x)))/2 // - (x*(2200-(3*x)))/2
R-((x*(2200-(3*x)))/2) = 0
R-((x*(2200-3*x))/2) = 0
(-1*x*(2200-3*x))/2+R = 0
(-1*x*(2200-3*x))/2+(2*R)/2 = 0
2*R-1*x*(2200-3*x) = 0
2*R+3*x^2-2200*x = 0
(2*R+3*x^2-2200*x)/2 = 0
(2*R+3*x^2-2200*x)/2 = 0 // * 2
2*R+3*x^2-2200*x = 0
2*R+3*x^2-2200*x = 0
DELTA = (-2200)^2-(2*3*4*R)
DELTA = 4840000-24*R
4840000-24*R = 0
4840000-24*R = 0 // - 4840000
-24*R = -4840000 // : -24
R = -4840000/(-24)
R = 605000/3
DELTA = 0 <=> t_3 = 605000/3
x = 2200/(2*3) i R = 605000/3
x = 1100/3 i R = 605000/3
( x = ((4840000-24*R)^(1/2)+2200)/(2*3) or x = (2200-(4840000-24*R)^(1/2))/(2*3) ) i R > 605000/3
( x = ((4840000-24*R)^(1/2)+2200)/6 or x = (2200-(4840000-24*R)^(1/2))/6 ) i R > 605000/3
R-605000/3 > 0
R-605000/3 > 0 // + 605000/3
R > 605000/3
x in { 1100/3, ((4840000-24*R)^(1/2)+2200)/6, (2200-(4840000-24*R)^(1/2))/6 }
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