Find $ \left(2x-5\right)^2 $ using formula.

$$ (A - B)^2 = \color{blue}{A^2} - 2 \cdot A \cdot B + \color{red}{B^2} $$

where $ A = \color{blue}{ 2x } $ and $ B = \color{red}{ 5 }$.

$$ \begin{aligned}\left(2x-5\right)^2 = \color{blue}{\left( 2x \right)^2} -2 \cdot 2x \cdot 5 + \color{red}{5^2} = 4x^2-20x+25\end{aligned} $$

Find $ \left(x-3\right)^3 $ using formula

$$ (A - B) = A^3 - 3A^2B + 3AB^2 - B^3 $$

where $ A = x $ and $ B = 3 $.

$$ \left(x-3\right)^3 = x^3-3 \cdot x^2 \cdot 3 + 3 \cdot x \cdot 3^2-3^3 = x^3-9x^2+27x-27 $$

Remove the parentheses by changing the sign of each term within them.

$$ - \left( x^3-9x^2+27x-27 \right) = -x^3+9x^2-27x+27 $$

Combine like terms:

$$ \color{blue}{4x^2} \color{red}{-20x} + \color{green}{25} -x^3+ \color{blue}{9x^2} \color{red}{-27x} + \color{green}{27} = -x^3+ \color{blue}{13x^2} \color{red}{-47x} + \color{green}{52} $$