Đáp án:
`a,`
$7 |x| - \dfrac{24}{\dfrac{3}{14} } =$ `|` $\dfrac{-3}{ \dfrac{11}{14} }$ `|`
`⇔ 7 |x| - 4/7 = | (-3)/154|`
`⇔7 |x| - 4/7 = 3/154`
`⇔ 7 |x| = 3/154 + 4/7`
`⇔ 7 |x| = 13/22`
`⇔ |x| = 13/22 ÷ 7`
`⇔ |x| = 13/154`
`⇔` \(\left[ \begin{array}{l}x=\dfrac{13}{154}\\x=\dfrac{-13}{154}\end{array} \right.\)
Vậy `x=13/154` hoặc `x=(-13)/154`
$\\$
`b,`
`3 × (-2)^{5x + 13} + 24 = 0`
`⇔ 3 × (-2)^{5x + 13}=0-24`
`⇔ 3 × (-2)^{5x + 13} = -24`
`⇔ (-2)^{5x + 13} = -24 ÷ 3`
`⇔ (-2)^{5x + 13} = -8`
`⇔ (-2)^{5x + 13} = -2^3`
`⇔ 5x + 13 = 3`
`⇔ 5x = 3 - 13`
`⇔ 5x = -10`
`⇔x = -10 ÷ 5`
`⇔ x=-2`
Vậy `x=-2`
