Đáp án:
$\text{x = $\dfrac{-1}{35}$ .}$
Giải thích các bước giải:
$\text{5x + 1 = $\sqrt{\dfrac{36}{49}}$.}$
$\text{⇒ 5x + 1 = $\sqrt{\dfrac{6^2}{7^2}}$.}$
$\text{⇒ 5x + 1 = $\dfrac{6}{7}$.}$
$\text{⇒ 5x = $\dfrac{6}{7}$ - 1.}$
$\text{⇒ 5x = $\dfrac{6}{7}$ - $\dfrac{7}{7}$ .}$
$\text{⇒ 5x = $\dfrac{-1}{7}$ .}$
$\text{⇒ x = $\dfrac{-1}{7}$ ÷ 5.}$
$\text{⇒ x = $\dfrac{-1}{7}$.$\dfrac{1}{5}$ .}$
$\text{⇒ x = $\dfrac{-1}{35}$ .}$
$\text{Vậy x = $\dfrac{-1}{35}$ .}$
