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