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D( x )
x = 0
x = 0
x = 0
x in (-oo:0) U (0:+oo)
4/x-3 = (x+3)/4 // - (x+3)/4
4/x-((x+3)/4)-3 = 0
(-1*(x+3))/4+4/x-3 = 0
(-1*x*(x+3))/(4*x)+(4^2)/(4*x)+(-3*4*x)/(4*x) = 0
16-1*x*(x+3)-3*4*x = 0
16-x^2-3*x-12*x = 0
16-x^2-15*x = 0
16-x^2-15*x = 0
16-x^2-15*x = 0
DELTA = (-15)^2-(-1*4*16)
DELTA = 289
DELTA > 0
x = (289^(1/2)+15)/(-1*2) or x = (15-289^(1/2))/(-1*2)
x = -16 or x = 1
(x+16)*(x-1) = 0
((x+16)*(x-1))/(4*x) = 0
((x+16)*(x-1))/(4*x) = 0 // * 4*x
(x+16)*(x-1) = 0
( x+16 )
x+16 = 0 // - 16
x = -16
( x-1 )
x-1 = 0 // + 1
x = 1
x in { -16, 1 }
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