\(a.\frac{2}{5}-x=-\frac{3}{10}\Leftrightarrow x=\frac{2}{5}+\frac{3}{10}=\frac{7}{10}\)\(b.x-\frac{1}{15}=\frac{3}{2}\Leftrightarrow x=\frac{1}{15}+\frac{3}{2}=\frac{47}{30}\)\(c.\frac{3}{8}-x=-\frac{5}{12}\Leftrightarrow x=\frac{3}{8}+\frac{5}{12}=\frac{19}{24}\)\(d.\frac{11}{13}-\left(\frac{5}{42}-x\right)=0\Leftrightarrow x=\frac{5}{42}-\frac{11}{13}=-\frac{397}{546}\)\(e.\frac{2}{3}x+\frac{5}{7}=\frac{3}{10}\Leftrightarrow\frac{2}{3}x=\frac{3}{10}-\frac{5}{7}=-\frac{29}{70}\Leftrightarrow x=-\frac{29}{70}:\frac{2}{3}=-\frac{87}{140}\)\(g.-5x\left(x-\frac{5}{4}\right)=0\Leftrightarrow\orbr{\begin{cases}x=0\\x-\frac{5}{4}=0\Leftrightarrow x=\frac{5}{4}\end{cases}}\)\(h.\left|x+\frac{3}{4}\right|=\frac{1}{2}\Leftrightarrow\orbr{\begin{cases}x+\frac{3}{4}=\frac{1}{2}\\x+\frac{3}{4}=-\frac{1}{2}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-\frac{1}{4}\\x=-\frac{5}{4}\end{cases}}}\)\(k.-\frac{21}{13}x+\frac{1}{3}=-\frac{2}{3}\Leftrightarrow-\frac{21}{13}x=-\frac{1}{3}-\frac{2}{3}=-1\Leftrightarrow x=\frac{13}{21}\)Câu trả lời: \(a.\frac{2}{5}-x=-\frac{3}{10}\Leftrightarrow x=\frac{2}{5}+\frac{3}{10}=\frac{7}{10}\)\(b.x-\frac{1}{15}=\frac{3}{2}\Leftrightarrow x=\frac{1}{15}+\frac{3}{2}=\frac{47}{30}\)\(c.\frac{3}{8}-x=-\frac{5}{12}\Leftrightarrow x=\frac{3}{8}+\frac{5}{12}=\frac{19}{24}\)\(d.\frac{11}{13}-\left(\frac{5}{42}-x\right)=0\Leftrightarrow x=\frac{5}{42}-\frac{11}{13}=-\frac{397}{546}\)\(e.\frac{2}{3}x+\frac{5}{7}=\frac{3}{10}\Leftrightarrow\frac{2}{3}x=\frac{3}{10}-\frac{5}{7}=-\frac{29}{70}\Leftrightarrow x=-\frac{29}{70}:\frac{2}{3}=-\frac{87}{140}\)\(g.-5x\left(x-\frac{5}{4}\right)=0\Leftrightarrow\orbr{\begin{cases}x=0\\x-\frac{5}{4}=0\Leftrightarrow x=\frac{5}{4}\end{cases}}\)\(h.\left|x+\frac{3}{4}\right|=\frac{1}{2}\Leftrightarrow\orbr{\begin{cases}x+\frac{3}{4}=\frac{1}{2}\\x+\frac{3}{4}=-\frac{1}{2}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-\frac{1}{4}\\x=-\frac{5}{4}\end{cases}}}\)\(k.-\frac{21}{13}x+\frac{1}{3}=-\frac{2}{3}\Leftrightarrow-\frac{21}{13}x=-\frac{1}{3}-\frac{2}{3}=-1\Leftrightarrow x=\frac{13}{21}\)

Giúp mình với

Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

Chọn lớp

Chọn môn

Trần Vi Thảo

14 tháng 9 2021 - olm

Giúp mình với

#Toán lớp 7

Nguyễn Minh Quang

Giáo viên

15 tháng 9 2021

\(a.\frac{2}{5}-x=-\frac{3}{10}\Leftrightarrow x=\frac{2}{5}+\frac{3}{10}=\frac{7}{10}\)

\(b.x-\frac{1}{15}=\frac{3}{2}\Leftrightarrow x=\frac{1}{15}+\frac{3}{2}=\frac{47}{30}\)

\(c.\frac{3}{8}-x=-\frac{5}{12}\Leftrightarrow x=\frac{3}{8}+\frac{5}{12}=\frac{19}{24}\)

\(d.\frac{11}{13}-\left(\frac{5}{42}-x\right)=0\Leftrightarrow x=\frac{5}{42}-\frac{11}{13}=-\frac{397}{546}\)

\(e.\frac{2}{3}x+\frac{5}{7}=\frac{3}{10}\Leftrightarrow\frac{2}{3}x=\frac{3}{10}-\frac{5}{7}=-\frac{29}{70}\Leftrightarrow x=-\frac{29}{70}:\frac{2}{3}=-\frac{87}{140}\)

\(g.-5x\left(x-\frac{5}{4}\right)=0\Leftrightarrow\orbr{\begin{cases}x=0\\x-\frac{5}{4}=0\Leftrightarrow x=\frac{5}{4}\end{cases}}\)

\(h.\left|x+\frac{3}{4}\right|=\frac{1}{2}\Leftrightarrow\orbr{\begin{cases}x+\frac{3}{4}=\frac{1}{2}\\x+\frac{3}{4}=-\frac{1}{2}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-\frac{1}{4}\\x=-\frac{5}{4}\end{cases}}}\)

\(k.-\frac{21}{13}x+\frac{1}{3}=-\frac{2}{3}\Leftrightarrow-\frac{21}{13}x=-\frac{1}{3}-\frac{2}{3}=-1\Leftrightarrow x=\frac{13}{21}\)

Đúng(0)