(x-6)² - 5
(x-6)² расскладываем по формуле a²-2ab+b²
x²-12x+36-5
x²-12x+31 (ax²+bx+c)
Решаем через D(Дискриминант)
D=b²-4ac
D=144-124
D=20 - √20
x1=-b+√D/2a
x1= 12+√20/2
x2=-b-√D/2a
x2=12-√20/2
12-9х-2=-9х+10
12-9х-2+9х-10=0
10=10
80 см= 8 дм
24 мм=2,4 см
3дм 4 см=34
4см= 40мм
38см=380
6см 7мм=67мм
Заметим: ![6^{n}-1\equiv 1^{n}-1(mod5)=1-1=0,n \in N_0=>(6^{n}-1)\vdots 5=>2*(6^{n}-1)\vdots 10=>6*(6^{n}-1)\vdots 10=>(6^{n+1}-6)\vdots 10=>6^{n+1}\equiv6(mod 10)](https://tex.z-dn.net/?f=6%5E%7Bn%7D-1%5Cequiv%201%5E%7Bn%7D-1%28mod5%29%3D1-1%3D0%2Cn%20%5Cin%20N_0%3D%3E%286%5E%7Bn%7D-1%29%5Cvdots%205%3D%3E2%2A%286%5E%7Bn%7D-1%29%5Cvdots%2010%3D%3E6%2A%286%5E%7Bn%7D-1%29%5Cvdots%2010%3D%3E%286%5E%7Bn%2B1%7D-6%29%5Cvdots%2010%3D%3E6%5E%7Bn%2B1%7D%5Cequiv6%28mod%2010%29)
![1)\:2017^{2018}+2018^{2019} - 117^{78}\equiv 7^{2018}+8^{2019} - 7^{78}(mod 10)=7^{78}*(7^{1940}-1)+8^{2019} =49^{39}*(49^{970}-1)+8*64^{1009}\equiv (-1)^{39}*((-1)^{970}-1)+8*4^{1009}(mod10)=(-1)*0+32*256^{252}\equiv 2*6^{252}(mod10)\equiv 2*6(mod10)=12\equiv 2(mod 10)](https://tex.z-dn.net/?f=1%29%5C%3A2017%5E%7B2018%7D%2B2018%5E%7B2019%7D%20-%20117%5E%7B78%7D%5Cequiv%207%5E%7B2018%7D%2B8%5E%7B2019%7D%20-%207%5E%7B78%7D%28mod%2010%29%3D7%5E%7B78%7D%2A%287%5E%7B1940%7D-1%29%2B8%5E%7B2019%7D%20%3D49%5E%7B39%7D%2A%2849%5E%7B970%7D-1%29%2B8%2A64%5E%7B1009%7D%5Cequiv%20%28-1%29%5E%7B39%7D%2A%28%28-1%29%5E%7B970%7D-1%29%2B8%2A4%5E%7B1009%7D%28mod10%29%3D%28-1%29%2A0%2B32%2A256%5E%7B252%7D%5Cequiv%202%2A6%5E%7B252%7D%28mod10%29%5Cequiv%202%2A6%28mod10%29%3D12%5Cequiv%202%28mod%2010%29)
![2)\:28^{30}*42^{47}+19^{2648}\equiv (-2)^{30}*2^{47}+(-1)^{2648}(mod10)=2^{77}+1=4*32^{15}+1\equiv 4*2^{15}+1(mod 10)=4*32^3+1\equiv 4*2^3+1(mod10)=4*8+1=33\equiv 3(mod10)](https://tex.z-dn.net/?f=2%29%5C%3A28%5E%7B30%7D%2A42%5E%7B47%7D%2B19%5E%7B2648%7D%5Cequiv%20%28-2%29%5E%7B30%7D%2A2%5E%7B47%7D%2B%28-1%29%5E%7B2648%7D%28mod10%29%3D2%5E%7B77%7D%2B1%3D4%2A32%5E%7B15%7D%2B1%5Cequiv%204%2A2%5E%7B15%7D%2B1%28mod%2010%29%3D4%2A32%5E3%2B1%5Cequiv%204%2A2%5E3%2B1%28mod10%29%3D4%2A8%2B1%3D33%5Cequiv%203%28mod10%29)
3) ![6^{127}:2=6^{126}*3\equiv6*3(mod10)=18\equiv 8(mod10)](https://tex.z-dn.net/?f=6%5E%7B127%7D%3A2%3D6%5E%7B126%7D%2A3%5Cequiv6%2A3%28mod10%29%3D18%5Cequiv%208%28mod10%29)
Ответ: 1)2; 2)3; 3)8
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Использованы свойства сравнения чисел по модулю
Ответ:
7,22 дм²
Пошаговое объяснение:
1,9 * 2 = 3,8 (дм) длина прямоугольника
3,8 * 1,9 = 7,22 (дм²) площадь прямоугольника