\(\left(3x-\frac{1}{2}\right)^2\ge0\Leftrightarrow A\ge-5\)

Dấu = xảy ra khi \(3x-\frac{1}{2}=0\)

\(3x=\frac{1}{2}\Rightarrow x=x=\frac{1}{6}\)

Vậy..

x ở đâu ?

C = \(25.\left(\frac{-1}{3}\right)^3\) \(+\frac{1}{5}\) \(-2.\left(\frac{-1}{2}\right)^2\) \(-\frac{1}{2}\)

C = \(25.\left(\frac{-1}{27}\right)+\frac{1}{5}\) \(-2.\frac{1}{4}\) \(-\frac{1}{2}\)

C = \(\frac{-25}{27}\) \(+\frac{1}{5}\) \(-\frac{1}{2}\) \(-\frac{1}{2}\)

C = \(\frac{-25}{27}\) \(+\frac{1}{5}\) \(-1\)

C = \(\frac{-125}{135}\) \(+\frac{27}{135}\) \(-\frac{135}{135}\)

C = \(\frac{-233}{135}\)

D =  \(-8.\left(\frac{3}{4}-\frac{1}{4}\right):\left(\frac{9}{4}-\frac{7}{6}\right)\)

D = \(-8.\frac{1}{2}\) \(.\frac{12}{13}\)

D = \(-4.\frac{12}{13}\)

D = \(\frac{-48}{13}\)

E = \(5\sqrt{16}\) \(-4\sqrt{9}\) \(+\sqrt{25}\) \(-0,3\sqrt{400}\)

E = \(5.4-4.3+5-0,3.20\)

E = \(20-12+5-6\)

E = \(8+\left(-1\right)\)

E = \(7\)

F = \(\left(\frac{-3}{2}\right)\) \(+\left|\frac{-5}{6}\right|\) \(-1\frac{1}{2}\) \(:6\)

F = \(\left(\frac{-3}{2}\right)\) \(+\frac{5}{6}\) \(-\frac{3}{2}\) \(.\frac{1}{6}\)

F = \(\left(\frac{-3}{2}\right)\) \(+\frac{5}{6}\) \(-\frac{1}{4}\) 

F = \(\left(\frac{-18}{12}\right)\) \(+\frac{10}{12}\) \(-\frac{3}{12}\)

F = \(\frac{-11}{12}\)

 Chúc cậu hk tốt ~ 

Làm cách nào bây giờ?

bạn đi hỏi mấy đứa bạn kết bạn ấy 

Đặt A = (1 + 2 + 2² + ....+2⁹⁹) 

          2A = (2 + 2² + 2³ +....+2¹⁰⁰)

     2A - A = (2 + 2² + 2³ +....+2¹⁰⁰) - (1 + 2 + 2² +....+2⁹⁹)

                = 2¹⁰⁰ - 1 - 2¹⁰⁰

                = -1

Vậy (1 + 2 + 2² +.....+ 2⁹⁹) - 2¹⁰⁰ = -1

Học tốt!!!

Nếu sai thì thôi!!!

\(A=\frac{15}{34}+\frac{7}{21}+\frac{9}{34}-1\frac{15}{17}+\frac{2}{3}\)

   \(=\frac{12}{17}+\frac{1}{3}-\frac{32}{17}+\frac{2}{3}\)

   \(=-\frac{20}{17}+\frac{1}{3}+\frac{2}{3}\)

   \(=-\frac{20}{17}+1\)

   \(=-\frac{3}{17}\)

\(B=16\frac{2}{7}:\left(-\frac{3}{5}\right)-28\frac{2}{7}:\left(-\frac{3}{5}\right)\)

   \(=\left(\frac{114}{7}-\frac{198}{7}\right):\left(-\frac{3}{5}\right)\)

   \(=\left(-12\right):\left(-\frac{3}{5}\right)\)

   \(=20\)

A\(=\frac{15}{34}+\frac{7}{21}+\frac{9}{34}-1\frac{15}{17}+\frac{2}{3}\)

\(=\left(\frac{15}{34}+\frac{9}{34}\right)+\left(\frac{7}{21}+\frac{2}{3}\right)-1\frac{15}{17}\)

\(=\left(\frac{14}{17}-\frac{15}{17}\right)+1-1\)

\(=-\frac{1}{17}\)

\(B=16\frac{2}{7}:\left(-\frac{3}{5}\right)-28\frac{2}{7}:\left(-\frac{3}{5}\right)\)

\(B=-\frac{3}{5}.\left(16\frac{2}{7}-28\frac{2}{7}\right)\)

\(B=-\frac{3}{5}.\left(-12\right)\)

\(B=\frac{36}{5}\)

Hoctot

Ta cóA= 3ⁿ⁺³+2ⁿ⁺³+3ⁿ⁺¹+2ⁿ⁺²=3ⁿ.27+2ⁿ.8+3ⁿ.3+2ⁿ.4=3ⁿ.(27+3)+2ⁿ.(8+4)=3ⁿ.30+2ⁿ.12

Vì 30 chia hết cho 6 ,12 chia hết cho 6 suy ra 3ⁿ.30 chia hết cho 6,2ⁿ.12 chia hết cho 6 

suy ra 3ⁿ.30+2ⁿ.12 chia hết cho 6

suy ra A chia hết cho 6