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x in (-oo:+oo)
13 = (5/13)*(4-(2*x))^2 // - (5/13)*(4-(2*x))^2
13-((5/13)*(4-(2*x))^2) = 0
(-5/13)*(4-2*x)^2+13 = 0
13-5/13*(4-2*x)^2 = 0
13-5/13*(4-2*x)^2 = 0
80/13*x-20/13*x^2+89/13 = 0
80/13*x-20/13*x^2+89/13 = 0
1/13*(80*x-20*x^2+89) = 0
80*x-20*x^2+89 = 0
DELTA = 80^2-(-20*4*89)
DELTA = 13520
DELTA > 0
x = (13520^(1/2)-80)/(-20*2) or x = (-13520^(1/2)-80)/(-20*2)
x = (52*5^(1/2)-80)/(-40) or x = (-52*5^(1/2)-80)/(-40)
1/13*(x-((52*5^(1/2)-80)/(-40)))*(x-((-52*5^(1/2)-80)/(-40))) = 0
1/13*(x-((52*5^(1/2)-80)/(-40)))*(x-((-52*5^(1/2)-80)/(-40))) = 0
( x-((-52*5^(1/2)-80)/(-40)) )
x-((-52*5^(1/2)-80)/(-40)) = 0 // + (-52*5^(1/2)-80)/(-40)
x = (-52*5^(1/2)-80)/(-40)
( x-((52*5^(1/2)-80)/(-40)) )
x-((52*5^(1/2)-80)/(-40)) = 0 // + (52*5^(1/2)-80)/(-40)
x = (52*5^(1/2)-80)/(-40)
x in { (-52*5^(1/2)-80)/(-40), (52*5^(1/2)-80)/(-40) }
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