80100 кг=80 т 100кг
837200 кг=837 т 200кг
5378кг=5т 378 кг
Дано уравнение:
x^3-2x^2-19x+20=0
преобразуем
<span><span>−19x+−2<span>x2</span>+<span>x3</span>−1+2+19=0</span><span>−19x+−2<span>x2</span>+<span>x3</span>−1+2+19=0</span></span>
или
<span><span>−19x+−2<span>x2</span>+<span>x3</span>−1−−2+19=0</span><span>−19x+−2<span>x2</span>+<span>x3</span>−1−−2+19=0</span></span>
<span><span>−19<span>(x−1)</span>+−2<span>(<span>x2</span>−1)</span>+<span>x3</span>−1=0</span><span>−19<span>(x−1)</span>+−2<span>(<span>x2</span>−1)</span>+<span>x3</span>−1=0</span></span>
<span><span>−19<span>(x−1)</span>+−2<span>(x−1)</span><span>(x+1)</span>+<span>(x−1)</span><span>(<span>x2</span>+x+<span>12</span>)</span>=0</span><span>−19<span>(x−1)</span>+−2<span>(x−1)</span><span>(x+1)</span>+<span>(x−1)</span><span>(<span>x2</span>+x+<span>12</span>)</span>=0</span></span>
Вынесем общий множитель -1 + x за скобки
получим:
<span><span><span>(x−1)</span><span>(−2<span>(x+1)</span>+<span>x2</span>+x+<span>12</span>−19)</span>=0</span><span><span>(x−1)</span><span>(−2<span>(x+1)</span>+<span>x2</span>+x+<span>12</span>−19)</span>=0</span></span>
или
<span><span><span>(x−1)</span><span>(<span>x2</span>−x−20)</span>=0</span><span><span>(x−1)</span><span>(<span>x2</span>−x−20)</span>=0</span></span>
тогда:
<span><span><span>x1</span>=1</span><span><span>x1</span>=1</span></span>
и также
получаем ур-ние
<span><span><span>x2</span>−x−20=0</span><span><span>x2</span>−x−20=0</span></span>
Это уравнение вида:<span>a*x^2 + b*x + c.
</span>Квадратное уравнение можно решить
с помощью дискриминанта.
<span>Корни квадратного уравнения:
</span>
где D = b^2 - 4*a*c - это дискриминант.
Т.к.
<span>a=1</span>
<span><span>b=−1</span>b</span>
<span>c=−20
</span><span>Т.к. D > 0, то уравнение имеет два корня.
</span><span>x2 = (-b + sqrt(D)) / (2*a)
</span><span>x3 = (-b - sqrt(D)) / (2*a)
</span>или
<span><span><span>x2</span>=5</span></span>
<span><span><span>x3</span>=−4</span></span>
Получаем окончательный ответ для x^3 - 2*x^2 - 19*x + 20 = 0:
<span><span><span>x1</span>=1</span></span>
<span><span><span>x2</span>=5</span></span>
<span><span><span>x3</span>=−4</span></span>
1) (68*2)+110=136+110=460 (руб)будут стоить 2 кг. апельсин и 1кг. груш
или
(68+68)+110=136+110=460(руб)
Пусть все рабочие на заводе = Х чел
1 цех = 2/5х
2 цех = 2/5 : 1 1/2х = 2/5 : 3/2х = 2/5 * 2/3х = 4/15х
3 цех = 4/15х + 100
2/5х + 4/15х + 4/15х + 100 = х
2/5х + 4/15х + 4/15х - х = - 100
6/15х + 4/15х + 4/15х - 15/15х = - 100
14/15х - 15/15х = - 100
- 1/15х = - 100
х = - 100 : (- 1/15)
х = 100 * 15
х =1500 чел всего рабочих на заводе