Hai bài này nha mọi người

Đáp án + Giải thích các bước giải:

Bài $\textbf{11}:$

$\textbf{1}\bigg)$

$\begin{align} x +\dfrac{1}{3} &=\dfrac{7}{3}\\ x&=\dfrac{7}{3} - \dfrac{1}{3} \\ x &= \dfrac{6}{3} \\ x&= 2 \end {align}$

Vậy $x = 2$

$\textbf{2}\bigg)$

$\begin{align} \dfrac{7}{8} - x &=\dfrac{3}{8}\\ x&=\dfrac{7}{8} - \dfrac{3}{8} \\ x &= \dfrac{4}{8} \\ x&= \dfrac{1}{2} \end {align}$

Vậy $x = \dfrac{1}{2}$

$\textbf{3}\bigg)$

$\begin{align} x - \dfrac{4}{5} &= \dfrac{6}{5} \\ x &= \dfrac{4}{5} + \dfrac{6}{5} \\ x&= \dfrac{10}{5} \\ x &= 2 \end {align}$

Vậy $x = 2$

$\textbf{4}\bigg)$

$\begin{align} \dfrac{2}{3} + x &= \dfrac{7}{3} \\ x &= \dfrac{7}{3} - \dfrac{2}{3} \\ x&= \dfrac{5}{3} \end {align}$

Vậy $x = \dfrac{5}{3}$

$\textbf{5}\bigg)$

$\begin{align} x - \dfrac{7}{3} &= \dfrac{5}{3} \\ x &= \dfrac{7}{3} + \dfrac{5}{3} \\ x&= \dfrac{12}{3} \\ x &= 4 \end {align}$

Vậy $x = 4$

$\textbf{6}\bigg)$

$\begin{align} x - \dfrac{1}{2} &= 2\dfrac{1}{2} \\ x &= 2\dfrac{1}{2} + \dfrac{1}{2} \\ x&= 2\dfrac{2}{2} \\ x &= 3 \end {align}$

Vậy $x = 3$

$\textbf{7}\bigg)$

$\begin{align} x +\dfrac{5}{6} &=\dfrac{7}{12}\\ x&=\dfrac{7}{12} - \dfrac{5}{6} \\ x&=\dfrac{7}{12} - \dfrac{10}{12} \\ x &= -\dfrac{3}{12} \\ x&= -\dfrac{1}{4} \end {align}$

Vậy $x = -\dfrac{1}{4}$

$\textbf{8}\bigg)$

$\begin{align} x +\dfrac{2}{7} &=\dfrac{5}{7}\\ x&=\dfrac{5}{7} - \dfrac{2}{7} \\ x &= \dfrac{3}{7} \end {align}$

Vậy $x = \dfrac{3}{7}$

$\textbf{9}\bigg)$

$\begin{align} x - \dfrac{4}{3} &= \dfrac{1}{3} \\ x &= \dfrac{4}{3} + \dfrac{1}{3} \\ x&= \dfrac{5}{3} \\ \end {align}$

Vậy $x = \dfrac{5}{3}$

$\textbf{10}\bigg)$

$\begin{align} x +\dfrac{5}{12} &=\dfrac{1}{2}\\ x&=\dfrac{1}{2} - \dfrac{5}{12} \\ x&=\dfrac{6}{12} - \dfrac{5}{12} \\ x &= \dfrac{1}{12} \end {align}$

Vậy $x = \dfrac{1}{12}$

Bài $\textbf{12}:$

$\textbg{1}\bigg)$

$\begin{align} x +\dfrac{1}{2} &=\dfrac{5}{3}\\ x&=\dfrac{5}{3} - \dfrac{1}{2} \\ x&=\dfrac{10}{6} - \dfrac{3}{6} \\ x &= \dfrac{7}{6} \end {align}$

Vậy $x = \dfrac{7}{6}$

$\textbf{2}\bigg)$

$\begin{align} \dfrac{4}{3} - x &=\dfrac{3}{5}\\ x&=\dfrac{4}{3} - \dfrac{3}{5} \\ x&=\dfrac{20}{15} - \dfrac{9}{15} \\ x &= \dfrac{11}{15} \end {align}$

Vậy $x = \dfrac{11}{15}$

$\textbf{3}\bigg)$

$\begin{align} \dfrac{3}{4} + x &=1\dfrac{1}{2}\\ \dfrac{3}{4} + x &= \dfrac{3}{2} \\ x&=\dfrac{3}{2} - \dfrac{3}{4} \\ x&=\dfrac{6}{4} - \dfrac{3}{4} \\ x &= \dfrac{3}{4} \end {align}$

Vậy $x = \dfrac{3}{4}$

$\textbg{4}\bigg)$

$\begin{align} x - \dfrac{4}{3} &=\dfrac{2}{9}\\ x&=\dfrac{2}{9} + \dfrac{4}{3} \\ x&=\dfrac{2}{9} + \dfrac{12}{9} \\ x &= \dfrac{14}{9} \end {align}$

Vậy $x = \dfrac{14}{9}$

$\textbg{5}\bigg)$

$\begin{align} x +\dfrac{7}{3} &=\dfrac{11}{6}\\ x&=\dfrac{11}{6} - \dfrac{7}{3} \\ x&=\dfrac{11}{6} - \dfrac{14}{6} \\ x &= -\dfrac{3}{6} \\ x &= -\dfrac{1}{2} \end {align}$

Vậy $x = -\dfrac{1}{2}$

$\textbg{6}\bigg)$

$\begin{align} x - \dfrac{1}{5} &=\dfrac{9}{10}\\ x&=\dfrac{9}{10} + \dfrac{1}{5} \\ x&=\dfrac{9}{10} + \dfrac{2}{10} \\ x &= \dfrac{11}{10} \end {align}$

Vậy $x = \dfrac{11}{10}$

$\textbg{7}\bigg)$

$\begin{align} x + \dfrac{5}{12} &=\dfrac{7}{8}\\ x&=\dfrac{7}{8} - \dfrac{5}{12} \\ x&=\dfrac{21}{24} - \dfrac{10}{24} \\ x &= \dfrac{11}{24} \end {align}$

Vậy $x = \dfrac{11}{24}$

$\textbg{8}\bigg)$

$\begin{align} x + \dfrac{3}{4} &=\dfrac{7}{6}\\ x&=\dfrac{7}{6} - \dfrac{3}{4} \\ x&=\dfrac{14}{12} - \dfrac{9}{12} \\ x &= \dfrac{5}{12} \end {align}$

Vậy $x = \dfrac{5}{12}$

$\textbg{9}\bigg)$

$\begin{align} x - \dfrac{2}{7} &=\dfrac{1}{35}\\ x&=\dfrac{1}{35} + \dfrac{2}{7} \\ x&=\dfrac{1}{35} + \dfrac{10}{35} \\ x &= \dfrac{11}{35} \end {align}$

Vậy $x = \dfrac{11}{35}$

$\textbg{10}\bigg)$

$\begin{align} x + \dfrac{1}{5} &=\dfrac{7}{10}\\ x&=\dfrac{7}{10} - \dfrac{1}{5} \\ x&=\dfrac{7}{10} - \dfrac{2}{10} \\ x &= \dfrac{5}{10}  \\ x &= \dfrac{1}{2} \end {align}$

Vậy $x = \dfrac{1}{2}$