(4/9+7/12+у)*(1-20/47)*(5/4-17/20)=3/10 нужно решение.

(37/36+у)*27/47*8/20=3/10,

37/36+у=(3*47*20)/(10*27*8),

у=47/72-37/36,

у=-3/8 

(43/36+y) * 27/47 * 8/20 = 3/10

(43/36+y) * 27/47 * 4/5 = 3/10 / 27/47*2/5

43/36+y=47/36

y=47/36-43/36

y=1/9