Задача 13927 27\x+5+1\x-5=2...

u21324219170

21.02.2017

27\x+5+1\x-5=2

SOVA

21.02.2017

★

(27*(х-5)+(х+5))/(х+5)(х-5)=2
(27х-135+х+5)/(x^2-25)=2
x^2-25≠0
28x-130=2x^2-50
x^2-14x+40=0
D=196-160=36
x1=(14-6)/2=4 или х=(14+6).2=10
О т в е т. 4; 10

vk196732551

22.02.2017

(27·(х–5)+(х+5))/(х+5)(х–5)=2 , (27х-135+х+5)/(х+5)*(х-5)=2 , (28х-130)/(х+5)*(х-5)=2 , 28х-130/(х+5)*(х-5)=2 , 28х-130/х+5*(х-5)=2,х≠-5, (28х-130)*(х-5)/х+5=2 , 28x2-140х-130х+650/х+5=2, , 28х2-270х+650=2(х+5), 28х2-270х+650-2(х+5)=0, 2(14х2-135х+325-(х+5))=0, 2(14х2-135+325-х-5)=0, 2(14х2-136х+320)=0, 2*2(7х2-68х+160)=0, 2*2(7х2-28х-40х+160)=0, 2*2(7х*(х-4)-40(х-4))=0, 2*2(7х-40)*(х-4)=0, (7х-40)*(х-4)=0, 7х-40=0, х-4=0, х=40/7,х≠-5, х=4, х=40/7 Ответ: х1= 40/7, х2=4