32+(136-х*8):4=64;21=75:(2х+13))*5+120;12*(32-(36+8х):5)+144;

1) 32 + (136 - х * 8) : 4 = 64;

(136 - х * 8) : 4 = 64 - 32;

(136 - х * 8) : 4 = 32;

136 - х * 8 = 32 * 4;

136 - х * 8 = 128;

136 - 128 = х * 8;

8 = х * 8;

х = 8 : 8;

х = 1.

2) 21 = 75 : (2х + 13) * 5 + 120;

21 - 120 = 75 : (2х + 13) * 5;

-99 = 75 : (2х + 13) * 5;

-99 * (2х + 13) * 5 = 75;

-99 * (2х + 13) = 75 : 5;

-99 * (2х + 13) = 15;

-198х - 1287 = 15;

-198х = 15 + 1287;

-198х = 1302;

х = 1302 : (-198);

х = -6 19/33.

3) 12 * (32 - (36 + 8х) : 5) = 144;

32 - (36 + 8х) : 5 = 144 : 12;

32 - (36 + 8х) : 5 = 12;

32 - 12 = (36 + 8х) : 5;

20 = (36 + 8х) : 5;

20 * 5 = 36 + 8х;

100 - 36 = 8х;

64 = 8х;

х = 64 : 8;

х = 8.