1) 6-4=2 км/час
10/2=5 час
Через 5 часов
2) при x от 1
<span><span><span>(<span>a+b</span>)</span> 2</span>=<span><span><span>a 2</span>+<span><span>2a</span>b</span></span>+<span>b 2</span></span></span><span>. сумма
</span><span><span><span>(<span>a−b</span>)</span> 2</span>=<span><span><span>a 2</span>+<span>b 2</span></span>−<span><span>2a</span>b</span></span></span><span> разность</span>
4х ³у-6х²у²=2х<span>²у(2х-3у)
5а</span> ³-15а²b+20аb²=5а(а²-3аb+4b<span>²)
6mn</span>²-9n ³+12m²n²=3n²(2m-3n+4m<span>²)</span>