\(\frac{2}{3}-x=\frac{3}{5}\Rightarrow x=\frac{2}{3}-\frac{3}{5}\Rightarrow x=\frac{1}{15}\Rightarrow-3.x=-3.\frac{1}{15}\Rightarrow-3.x=-0,2\)

\(\frac{x^9-1}{x^9+1}=7\)=>x⁹-1=7x⁹+1

=>x⁹=\(\frac{-8}{6}\)

=>(x⁹)²=(\(\frac{-8}{6}\))²

=>x¹⁸=\(\frac{16}{9}\)=>..................................

mơn bạn

x = 1/8 = 0,125

mk thi rùi 300đ

x= 0,125

1. 21x=11

2.-0,25

3.\(\frac{-1}{5}\)

4. 14,4m

5. 4 điểm

1) 11

2) -0,25

3) 1/5

4) 9,6

5) 4 

⇒ \(\frac{5}{8}x=\frac{23}{4}+\frac{1}{8}\)

⇒ \(\frac{5}{8}x=\frac{47}{8}\)

⇒ \(x=\frac{47}{8}:\frac{5}{8}\)

⇒ \(x=\frac{47}{5}\)

\(A=2^0+2^1+2^2+...+2^{21}\)

\(2A=2^1+2^2+2^3+...+2^{22}\)

\(2A-A=\left(2^1+2^2+2^3+...+2^{22}\right)-\left(2^0+2^1+2^2+...+2^{21}\right)\)

\(A=2^{22}-1\)

\(2^{22}-1=2^{2n}-1\)

\(2^{2\times11}-1=2^{2n}-1\)

n = 11

câu 1: 11

câu 2: 0,125

câu 3: -1;0;1

câu 4: -2,5

\(\dfrac{2^{12^{ }}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^5}-\dfrac{5^{10}.7^3-25^5.49^2}{\left(125.7\right)^3+5^9.14^3}\)

= \(\dfrac{2^{12}.3^5-2^{12}.3^4}{2^{12}.3^6+2^{12}.3^5}-\dfrac{5^{10}.7^3-5^{10}.7^4}{5^9.7^3+5^9.14^3}\)

= \(\dfrac{2^{12}\left(3^5-3^4\right)}{2^{12}\left(3^6+3^5\right)}-\dfrac{5^{10}\left(7^3-7^4\right)}{5^9\left(7^3+14^3\right)}\)

=\(\dfrac{3^5-3^4}{3^6+3^5}-\dfrac{5\left(7^3-7^4\right)}{7^3+14^3}\)

=\(\dfrac{243-81}{729+243}-\dfrac{5\left(343-2401\right)}{343+2744}\)

=\(\dfrac{162}{972}-\dfrac{5\left(-2058\right)}{3087}\)

=\(\dfrac{1}{6}-\dfrac{-10}{3}\)

= \(\dfrac{1}{6}+\dfrac{20}{6}\)

=\(\dfrac{21}{6}=3,5\)