1) сначала раскрываем скобки
(23/5)t+23/8-t=2и3/5-3t+3/4
(4и3/5)t-t+3t=3/4+2и3/5-2и7/8
(6и3/5)t=30/40+2и24/40-2и35/40
(33/5)t=19/40
t=19/40 : 33/5
t=19/40 x 5/33
t=19/264
2) (32/3) x 9-10и2/3k+81=107- 1/3k+20
96-10и2/3k+81=107-1/3k+20
1/3k-10и2/3k=107+20-96-81
-10и1/3k=-50
k=50 : (10и1/3)
k=50 x (3/31)
k=150/31
k=4и26/31