(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:

\[ y^2 - 18y + 81. \]