в) (2-y)²-у(у+2,5)=4

в)
\[(2-y)^2 - y(y+2.5) = 4\]
\[4 - 4y + y^2 - y^2 - 2.5y = 4\]
\[4 - 6.5y = 4\]
\[-6.5y = 0\]
\[y = 0\]
Ответ: y = 0