(х+1)^2/х-1 - 20/(х+4)(х-1) + х+1/х+4=х+1 - вопрос №79385941212041141 от larkina2000 23.03.2020 05:41

Question

Математика: (х+1)^2/х-1 - 20/(х+4)(х-1) + х+1/х+4=х+1

larkina2000 · Answer

(х+1)^2/х-1 - 20/(х+4)(х-1) + х+1/х+4=х+1
(х+1)^2*(x+4) - 20 + (x+1)(x-1) = (x+1)(x-1)(x+4)
(x^2 + 2x + 1)(x+4) - 20 + x^2 - 1 = (x^2-1)(x+4)
x^3+2x^2+x+4x^2+8x+4-20+x^2-1 = x^3 - x +4x^2 - 4
3x^2 + 10x - 13 = 0
D = 100-4*(-13)*3 = 256
x1 = (-10 + 16)/(2*3) = 1
x2 = (-10 - 16)/(2*3) = -13/3