283. Multiply: $4 x-5$ and $2 x-3$.
283. $(4 x-5)(2 x-3)=8 x^{2}-22 x+15$. Interestingly, in the manuscript, the calculation is carried out as follows:

$$
\begin{aligned}
& 4 x \cdot 2 x=8 x^{2} \\
& 3 \cdot 4 x=-12 x \\
& 5 \cdot 2 x=-10 x
\end{aligned}
$$

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