(9-у)²

The expression \((9 - y)^2\) can be expanded using the formula \((a - b)^2 = a^2 - 2ab + b^2\). In your case, let \(a = 9\) and \(b = y\): \[ (9 - y)^2 = 9^2 - 2 \cdot 9 \cdot y + y^2 \] Calculating each term: \[ 9^2 = 81, \] \[ -2 \cdot 9 \cdot y = -18y, \] \[ y^2 = y^2. \] Now, combine these: \[ (9 - y)^2 = 81 - 18y + y^2. \] So the expanded form of \((9 - y)^2\) is: \[ y^2 - 18y + 81. \]