Ответ:

х=25 и х=3

Пошаговое объяснение:

93/(1+(120/(1+(78/(1+х)))))=3

1+(120/(1+(78/(1+х))))=93/3

1+(120/(1+(78/(1+х))))=31

120/(1+(78/(1+х)))=31-1

120/(1+(78/(1+х)))=30

1+(78/(1+х)))=120/30

1+(78/(1+х))=4

78/(1+х)=4-1

78/(1+х)=3

1+х=78/3

1+х=26

х=26-1

х=25

Проверка: 93/(1+(120/(1+(78/(1+25)))))=3; 93/(1+(120/(1+(78/26))))=3; 93/(1+(120/(1+3)))=3; 93/(1+(120/4))=3; 93/(1+30)=3; 93/31=3; 3=3.

1/(1+(19/(10+3*(15/(2+х)))))=1/2

1+(19/(10+3*(15/(2+х))))=1/(1/2)

1+(19/(10+3*(15/(2+х))))=2

19/(10+3*(15/(2+х)))=2-1

19/(10+3*(15/(2+х)))=1

10+3*(15/(2+х))=19/1

10+3*(15/(2+х))=19

3*(15/(2+х))=19-10

3*(15/(2+х))=9

15/(2+х)=9/3

15/(2+х)=3

2+х=15/3

2+х=5

х=5-2

х=3

Проверка:

1/(1+(19/(10+3*(15/(2+3)))))=1/2; 1/(1+(19/(10+3*(15/5))))=1/2; 1/(1+(19/(10+3*3)))=1/2; 1/(1+(19/(10+9)))=1/2; 1/(1+(19/19))=1/2; 1/(1+1)=1/2; 1/2=1/2