1. \(10.\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\)
2 Tìm số tự nhiên x,y sao cho \(10^x+48=y^2\)
Câu 1 : Số tự nhiên a :7 dư 1,số tự nhiên b :7 dư 2,số tự nhiên c:7 dư 4.Chứng minh
a,a+b+c chia hết cho 7
b,a-b+c ko chia hết cho 7
Câu 2:Thực hiện phép tính:
B=10. 4^6.9^5+6^9.120 phần 8^4.3^12-6^11(chú ý:10 ko thuộc phân số bên)
Câu 3: Chứng tỏ:Nếu (ab+cd) chia hết cho 11 thì abcd chia hết cho 11(ab,cd,abcd đều có gạch ngang trên đầu)
Câu 4:Cho x,y thuộc N,chứng minh:Nếu(x+2y) chia hết 5 thì (3x-4y) chia hết 5
Câu 5:Tìm tự nhiên x,y sao cho 10^x +48=y^2
ai làm hết đc mik cho 1 tick
\(\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}.10\)
\(\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}.10=\frac{2^{12}.3^{10}+2^9.3^9.120}{2^{12}.3^{12}-2^{11}.3^{11}}.10=\frac{2^{10}.3^{10}\left(2^2+20\right)}{2^{10}.3^{10}\left(6^2-6\right)}.10=\frac{24.10}{30}=8\)
\(10.\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\)
10.46.95+69.120 :; 84.312-611
Rút gọn biểu thức: \(10.\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\)
tính biểu thức \(10.\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\)
=5^1+3+5+7+.....+49
Số các số hạng từ 1 đến 49 là (49-1):1+1=50
Tổng các số từ 1 đên 49 là (49+1).50:2=1250
=5^1250
1) Tính nhanh:
\(10\cdot\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\)
Đầu tiên ta rút gọn \(\frac{4^{^6}.9^{^5}+6^{^9}.120}{8^{^4}.3^{^{12}}-6^{^{11}}}\)= \(\frac{2^{^{12}}.3^{^{10}}+2^{^9}.3^{^9}.2^{^3}.3.5}{2^{^{12}}.3^{^{12}}-2^{^{11}}-3^{^{11}}}\)= \(\frac{2^{^{12}}.3^{^{10}}+2^{^{12}}.3^{^{10}}.5}{2^{^{12}}.3^{^{12}}-2^{^{11}}.3^{^{11}}}\)= \(\frac{2^{^{12}}.3^{^{10}}.\left(1+5\right)}{2^{^{11}}.3^{^{11}}.\left(6-1\right)}\)= \(\frac{2.6}{3.5}\)= \(\frac{12}{15}\)= \(\frac{4}{5}\)
\(\Rightarrow\)10 . \(\frac{4}{5}\)= \(\frac{40}{5}\)= 8
Tính hợp lí :
a ) 10 . \(\frac{4^6.9^5+6^9.120}{8^4.3^{12}.6^{11}}\)
Sửa đề : \(10.\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\)
\(10\cdot\frac{4^6\cdot9^5+6^9\cdot120}{8^4\cdot3^{12}-6^{11}}\)
\(=10\cdot\frac{2^{12}\cdot3^{10}+2\cdot9\cdot3^9\cdot2^3\cdot3\cdot5}{2^{12}.3^{12}-2^{11}.3^{11}}\)
\(=10\cdot\frac{2^{12}\cdot3^{10}\cdot\left(1+5\right)}{2^{11}\cdot3^{11}\cdot\left(2\cdot3-1\right)}\)
\(=10\cdot\frac{2\cdot6}{3\cdot5}=8\)
Bài làm:
\(10.\frac{4^6.9^5+6^9.120}{8^4.3^{12}.6^{11}}\)
\(=\frac{2.5.2^{12}.3^{10}+2^9.3^9.2.5.2^2.3}{2^{12}.3^{12}.2^{11}.3^{11}}\)
\(=\frac{2^{13}.3^{10}.5+2^{12}.3^{10}.5}{2^{23}.3^{23}}\)
\(=\frac{2^{12}.3^{10}.5\left(2+1\right)}{2^{23}.3^{23}}\)
\(=\frac{2^{12}.3^{11}.5}{2^{23}.3^{23}}=\frac{5}{2^{11}.3^{12}}\)
sợ sai
tính:
a)\(\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\)
b)\(\frac{2^{15}.9^4}{6^3.8^3}\)
c)\(\frac{8^{10}+4^{10}}{8^4+4^{11}}\)
\(a,\) \(\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\)
\(=\frac{2^{12}.3^{10}+\left(2.3\right)^9.2^3.3.5}{2^{12}.3^{12}-\left(2.3\right)^{11}}\)
\(=\frac{2^{12}.3^{10}+2^9.3^9.2^3.3.5}{2^{12}.3^{12}-2^{11}.3^{11}}\)
\(=\frac{2^{12}.3^{10}+2^{12}.3^{10}.5}{2^{12}.3^{12}-2^{11}.3^{11}}\)
\(=\frac{\left(2^{12}.3^{10}\right)\left(1+5\right)}{\left(2^{11}.3^{11}\right)\left(2.3-1\right)}\)
\(=\frac{\left(2^{12}.3^{10}\right).6}{\left(2^{11}.3^{11}\right).5}\)
\(=\frac{2.6}{3.5}\)
\(=\frac{2.2}{5}\)
\(=\frac{4}{5}\)
\(b,\) \(\frac{2^{15}.9^4}{6^3.8^3}\)
\(=\frac{2^{15}.3^8}{2^3.3^3.2^9}\)
\(=\frac{2^{15}.3^8}{2^{12}.3^3}\)
\(=2^3.3^5\)
\(=8.243\)
\(=1944\)
Chúc bạn học tốt ^^
a) \(\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}=\frac{\left(2^2\right)^6.\left(3^2\right)^5+6^9.120}{\left(2^3\right)^4.3^{12}-6^{11}}=\frac{2^{12}.3^{10}+6^9.120}{2^{12}.3^{12}-6^{11}}=\frac{6^{10}.4+6^{10}.20}{6^{12}-6^{11}}=\frac{6^{10}.\left(4+20\right)}{6^{11}.\left(6-1\right)}=\frac{6^{11}.4}{6^{11}.5}=\frac{4}{5}\)
b) \(\frac{2^{15}.9^4}{6^3.8^3}=\frac{2^{15}.\left(3^2\right)^4}{\left(2.3\right)^3.\left(2^3\right)^3}=\frac{2^{15}.3^8}{2^3.3^3.2^9}=\frac{2^{15}.3^8}{2^{12}.3^3}=2^3.3^5=1944\)
c) \(\frac{8^{10}+4^{10}}{8^4+4^{11}}=\frac{\left(4.2\right)^{10}+4^{10}}{\left(2^3\right)^4+4^6.4^5}=\frac{4^{10}.2^{10}+4^{10}}{2^{12}+4^6.4^5}=\frac{4^{10}.\left(2^{10}+1\right)}{4^6+4^6.2^{10}}=\frac{4^{10}.\left(2^{10}+1\right)}{4^6.\left(1+2^{10}\right)}=\frac{4^{10}}{4^6}=4^4=256\)
Tính hợp lí:
\(10\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\)