Ну в принципе вот так,все вроде расписала)))
А)<span><span>(<span><span>x2</span>+x</span>)</span><span>(<span>49−<span>x2</span></span>)</span>=</span>Раскрытие скобок:<span><span>x2</span>49+<span>x4</span><span>(<span>−1</span>)</span>+x49+<span>x3</span><span>(<span>−1</span>)</span>=</span><span>49<span>x2</span>−<span>x4</span>+49x−<span>x3</span>=</span><span>−<span>x4</span>−<span>x3</span>+49<span>x2</span>+49x</span>Ответ: <span>−<span>x4</span>−<span>x3</span>+49<span>x2</span>+49x
В)</span><span><span>(<span><span>x2</span>−7</span>)</span><span>(<span><span>x2</span>+18</span>)</span>=</span>Раскрытие скобок:<span><span>x4</span>+<span>x2</span>18−7<span>x2</span>−126=</span><span><span>x4</span>+11<span>x2</span>−126</span>Ответ: <span><span>x4</span>+11<span>x2</span>−126
Д)</span><span><span>(<span><span>x2</span>−3<span>x2</span></span>)</span><span>(<span><span>x2</span>+7</span>)</span>=</span>Приведение подобных:<span><span>(<span>−2<span>x2</span></span>)</span><span>(<span><span>x2</span>+7</span>)</span>=</span>Раскрытие скобок:<span>−2<span>x4</span>−14<span>x2</span></span>Ответ: <span><span>−2<span>x4</span>−14<span>x2
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Ответ:х=1, y=1
x=3-2y. Подставляем во второе уравнение 5(3-2y)-3y=2
-13y=13 отсюда y=1 и соответственно х=1