4x/7-7/x=42

Solution for 4x/7-7/x=42 equation:

D( x )

x = 0

x = 0

x = 0

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

(4*x)/7-(7/x) = 42 // - 42

(4*x)/7-(7/x)-42 = 0

(4*x)/7-7*x^-1-42 = 0

4/7*x^1-7*x^-1-42*x^0 = 0

(4/7*x^2-42*x^1-7*x^0)/(x^1) = 0 // * x^2

x^1*(4/7*x^2-42*x^1-7*x^0) = 0

x^1

(4/7)*x^2-42*x-7 = 0

(4/7)*x^2-42*x-7 = 0

DELTA = (-42)^2-(-7*4*(4/7))

DELTA = 1780

DELTA > 0

x = (1780^(1/2)+42)/(2*(4/7)) or x = (42-1780^(1/2))/(2*(4/7))

x = 7/8*(2*445^(1/2)+42) or x = 7/8*(42-2*445^(1/2))

x in { 7/8*(42-2*445^(1/2)), 7/8*(2*445^(1/2)+42)} 

x in { 7/8*(42-2*445^(1/2)), 7/8*(2*445^(1/2)+42) }