\(23,4-1,7\times13,76=0,008\)

=> Chọn D

bn lm sai hoàn toàn

 trả lời giúp tui

\(x-\dfrac{4}{8}=\dfrac{5}{18}\\ x=\dfrac{5}{18}+\dfrac{4}{8}\\ x=\dfrac{5}{18}+\dfrac{1}{2}\\ x=\dfrac{5}{18}+\dfrac{9}{18}\\ x=\dfrac{5+9}{18}\\ x=\dfrac{14}{18}\\ x=\dfrac{7}{9}\)

câu g là 1 và 1/7 ạ?

\(1,\)

\(a,\dfrac{-9}{51}.\dfrac{17}{6}\)

\(=-1.\dfrac{1}{2}\)

\(=-\dfrac{1}{2}\)

\(b,\dfrac{-25}{32}.\left(-0,2\right)\)

\(=\dfrac{-25}{32}.-\dfrac{2}{10}\)

\(=\dfrac{-5}{16}.-\dfrac{1}{2}\)

\(=\dfrac{5}{32}\)

\(c,-15,2.3,5=-53,2\)

\(d,\dfrac{-8}{15}.1\dfrac{1}{4}\)

\(=\dfrac{-8}{15}.\dfrac{5}{4}\)

\(=\dfrac{-2}{3}.\dfrac{1}{1}\)

\(=\dfrac{-2}{3}\)

\(e,1\dfrac{2}{5}.\dfrac{-3}{14}\)

\(=\dfrac{7}{5}.\dfrac{-3}{14}\)

\(=\dfrac{1}{5}.\dfrac{-3}{2}\)

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

\(g,1\dfrac{1}{17}.1\dfrac{1}{36}\)

\(=\dfrac{18}{17}.\dfrac{37}{36}\)

\(=\dfrac{1}{17}.\dfrac{37}{2}\)

\(=\dfrac{37}{34}\)

\(#T.T\)

\(\left(1+\dfrac{1}{2}-\dfrac{1}{4}\right)^2\times\left(2+\dfrac{3}{7}\right)\\ =\left(\dfrac{4}{4}+\dfrac{2}{4}-\dfrac{1}{4}\right)^2\times\left(\dfrac{14}{7}+\dfrac{3}{7}\right)\\ =\left(\dfrac{5}{4}\right)^2\times\dfrac{17}{7}\\ =\dfrac{25}{16}\times\dfrac{17}{7}=\dfrac{425}{112}\)

Bạn nhấn vào biểu tượng Σ để nhập công thức toán học bạn nha!

\(#BecauseI'maStrongGirl\)

a) OA//IC => \(\widehat{CKB}=\widehat{AOK}=50^o\) (đồng vị) 

OB//DE => \(\widehat{CID}=\widehat{CKB}=50^o\) (đồng vị) 

b) Mà: \(\widehat{CIE}+\widehat{CID}=180^o\) (kề bù)

=> \(\widehat{CIE}=180^o-\widehat{CID}\)

=> \(\widehat{CIE}=180^o-50^o=130^o\)

Ta có: \(x^2+y^2+z^2+\dfrac{1}{x^2}+\dfrac{1}{y^2}+\dfrac{1}{z^2}=6 \)

\(\Leftrightarrow x^2+y^2+z^2+\dfrac{1}{x^2}+\dfrac{1}{y^2}+\dfrac{1}{z^2}-6=0\\ \Leftrightarrow\left(x^2+\dfrac{1}{x^2}-2\right)+\left(y^2+\dfrac{1}{y^2}-2\right)+\left(z^2+\dfrac{1}{z^2}-2\right)=0\\ \Leftrightarrow\left(x^2-2\cdot x^2\cdot\dfrac{1}{x^2}+\dfrac{1}{x^2}\right)+\left(y^2-2\cdot y^2\cdot\dfrac{1}{y^2}+\dfrac{1}{y^2}\right)+\left(z^2-2\cdot z^2\cdot\dfrac{1}{z^2}+\dfrac{1}{z^2}\right)=0\\ \Leftrightarrow\left(x-\dfrac{1}{x}\right)^2+\left(y-\dfrac{1}{y}\right)^2+\left(z-\dfrac{1}{z}\right)^2=0\)

Mà: \(\left\{{}\begin{matrix}\left(x-\dfrac{1}{x}\right)^2\ge0\forall x\\\left(y-\dfrac{1}{y}\right)^2\ge0\forall y\\\left(z-\dfrac{1}{z}\right)^2\ge0\forall z\end{matrix}\right.=>\left(x-\dfrac{1}{x}\right)^2+\left(y-\dfrac{1}{y}\right)^2+\left(z-\dfrac{1}{z}\right)^2\ge0\forall x,y,z\) 

Dấu "=" xảy ra khi: \(\left\{{}\begin{matrix}x=\dfrac{1}{x}\\y=\dfrac{1}{y}\\z=\dfrac{1}{z}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x^2=1\\y^2=1\\z^2=1\end{matrix}\right.\)  

\(P=x^{2024}+y^{2024}+z^{2024}\\=\left(x^2\right)^{1012}+\left(y^2\right)^{1012}+\left(z^2\right)^{1012}\\ =1^{1012}+1^{1012}+1^{1012}=3\)

Trên nửa mặt phẳng có bờ chứa tia Ox, có 2 tia oz và oy mà góc xOz < góc xOy ( 30độ < 110 độ) nên tia Oz nằm giữa 2 tia Ox và Oy

Ta có : xOz  +  zOy  =  xOy 

           30   +  zOy  =   110

                      zoy   = 110 - 30 = 80

ot là tia phân giác của zOy nen zot = toy =  80 : 2 = 40

xot = zot + xoz = 40 + 30 = 70

vậy 

      yOz = 80 độ

      zOt =  40 độ

      xOt =  70 độ