(x-90)/90=140/(x-50)*2

Solution for (x-90)/90=140/(x-50)*2 equation:

D( x )

x-50 = 0

x-50 = 0

x-50 = 0

x-50 = 0 // + 50

x = 50

x in (-oo:50) U (50:+oo)

(x-90)/90 = 2*(140/(x-50)) // - 2*(140/(x-50))

(x-90)/90-(2*(140/(x-50))) = 0

(x-90)/90-280*(x-50)^-1 = 0

(x-90)/90-280/(x-50) = 0

((x-90)*(x-50))/(90*(x-50))+(-280*90)/(90*(x-50)) = 0

(x-90)*(x-50)-280*90 = 0

x^2-140*x-20700 = 0

x^2-140*x-20700 = 0

x^2-140*x-20700 = 0

DELTA = (-140)^2-(-20700*1*4)

DELTA = 102400

DELTA > 0

x = (102400^(1/2)+140)/(1*2) or x = (140-102400^(1/2))/(1*2)

x = 230 or x = -90

(x+90)*(x-230) = 0

((x+90)*(x-230))/(90*(x-50)) = 0

((x+90)*(x-230))/(90*(x-50)) = 0 // * 90*(x-50)

(x+90)*(x-230) = 0

( x+90 )

x+90 = 0 // - 90

x = -90

( x-230 )

x-230 = 0 // + 230

x = 230

x in { -90, 230 }