(7-а)²

To expand the expression \((7 - a)^2\), you can use the formula for the square of a binomial, which is \((x - y)^2 = x^2 - 2xy + y^2\).

Here, \(x = 7\) and \(y = a\).

Applying the formula:

\[ (7 - a)^2 = 7^2 - 2 \cdot 7 \cdot a + a^2 \]

Calculate each term:

• \(7^2 = 49\)
• \(-2 \cdot 7 \cdot a = -14a\)
• \(a^2 = a^2\)

Putting it all together:

\[ (7 - a)^2 = 49 - 14a + a^2 \]

So, the expanded form of \((7 - a)^2\) is:

\[ a^2 - 14a + 49 \]