![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
Em kiểm tra lại đề bài nhé! Tham khảo link:
Câu hỏi của Phan Thúy Vy - Toán lớp 7 - Học toán với OnlineMath
![](https://rs.olm.vn/images/avt/0.png?1311)
P = 32 + 62 + 92 + ... + 302
P = 32 . (12 + 22 + 32 + ... + 102)
P = 9 . 385
P = 3465
a) C = 106 + 57
C = 26 . 56 + 57
C = 56 . (26 + 5)
C = 56 . (64 + 5)
C = 56 . 69 chia hết cho 69
b) 310 . 199 - 39 . 500
= 39 . (3.199 - 500)
= 39 . (597 - 500)
= 39 . 97 chia hết cho 97
![](https://rs.olm.vn/images/avt/0.png?1311)
a)\(\left(\frac{1}{5}\right)^{10}.5^{20}=\left(\frac{1}{5}\right)^{10}.5^{10.2}=\left(\frac{1}{5}\right)^{10}.25^{10}=\left(\frac{1}{5}.5\right)^{10}=1^{10}=1\)
b)\(5^2.3^5.\left(\frac{3}{5}\right)^2=\left(\frac{3}{5}.5\right)^2.3^5=3^2.3^5=3^7\)
c)\(\left(\frac{1}{16}\right)^3:\left(\frac{1}{8}\right)^2=\left(\frac{1}{8}\right)^{2.3}:\left(\frac{1}{8}\right)^2=\left(\frac{1}{8}\right)^{6+2}=\left(\frac{1}{8}\right)^8\)
\(a.\left(\frac{1}{5}\right)^{10}.5^{20}=\left(\frac{1}{5}\right)^{10}.5^{10.2}=\left(\frac{1}{5}\right)^{10}.\left(5^2\right)^{10}=\left(\frac{1}{5}\right)^{10}.25^{10}=\left(\frac{1}{5}.25\right)^{10}=5^{10}.\)
\(b.5^2.3^5.\left(\frac{3}{5}\right)^2=\left[5^2.\left(\frac{3}{5}\right)^2\right].3^5=\left(5.\frac{3}{5}\right)^2.3^5=3^2.3^5=3^7\)\(c.\left(\frac{1}{16}\right)^3:\left(\frac{1}{8}\right)^2=\left[\left(\frac{1}{4}\right)^2\right]^3:\left[\left(\frac{1}{2}\right)^3\right]^2=\left(\frac{1}{4}\right)^6:\left(\frac{1}{2}\right)^6=\left(\frac{1}{4}:\frac{1}{2}\right)^6=\left(\frac{1}{2}\right)^6\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(a,\)\(\frac{x^7}{81}=27\)
\(\Rightarrow x^7=3^3.3^4=3^7\)
\(\Rightarrow x=3\)
\(b,\left(x^2\right)^4=\frac{x^{18}}{x^{10}}\)
\(\Rightarrow x^{18}=x^{10}.x^6\)
\(\Rightarrow x^{18}-x^{16}=0\)
\(\Rightarrow x^{16}\left(x^2-1\right)=0\)
\(\Rightarrow x^{16}\left(x-1\right)\left(x+1\right)=0\)
\(\Rightarrow\hept{\begin{cases}x=0\\x=\pm1\end{cases}}\)
\(\frac{x^7}{81}=27\Rightarrow x^7=27\cdot81=2187\)
\(x^7=2187\Leftrightarrow x^7=3^7\Rightarrow x=3\)
Vậy x=3
![](https://rs.olm.vn/images/avt/0.png?1311)
\(2^3+\left(\dfrac{1}{5}\right)^4+5^4=8+\dfrac{1}{625}+625=\dfrac{5000+1+625^2}{625}=\dfrac{395626}{625}\)
\(Sửa:2^3+\left(\dfrac{1}{5}\right)^4\cdot5^4=8+\left(\dfrac{1}{5}\cdot5\right)^4=8+1=9\)