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x in (-oo:+oo)
(8*x^2-513)/5 = 3*x // - 3*x
(8*x^2-513)/5-(3*x) = 0
(8*x^2-513)/5-3*x = 0
(8*x^2-513)/5+(-3*5*x)/5 = 0
8*x^2-3*5*x-513 = 0
8*x^2-15*x-513 = 0
8*x^2-15*x-513 = 0
8*x^2-15*x-513 = 0
DELTA = (-15)^2-(-513*4*8)
DELTA = 16641
DELTA > 0
x = (16641^(1/2)+15)/(2*8) or x = (15-16641^(1/2))/(2*8)
x = 9 or x = -57/8
(x+57/8)*(x-9) = 0
((x+57/8)*(x-9))/5 = 0
((x+57/8)*(x-9))/5 = 0 // * 5
(x+57/8)*(x-9) = 0
( x+57/8 )
x+57/8 = 0 // - 57/8
x = -57/8
( x-9 )
x-9 = 0 // + 9
x = 9
x in { -57/8, 9 }
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