Question

Решить уравнение
72/(х+5) + 54/(х-5)=9

Answer 1

(72(x-5) +54(x+5)) /(x² -25) =9

72x -360 +54x +270 =9(x² -25)

126x -90 -9x² +225 =0

-9x² +126x +135 =0; :(-9)

x² -14x -15 =0

D =14² +4*15=256=16²

x1=(14-16)/2 = -1

x2=(14+16)/2=15