Tìm x a, (2x – 3)² = 16 b, ( -1/3)³ . x = 1/81 16/07/2021 Bởi Charlie Tìm x a, (2x – 3)² = 16 b, ( -1/3)³ . x = 1/81
CHÚC BẠN HỌC TỐT!!! Trả lời: $a, (2x-3)^2=16$ \(⇔\left[ \begin{array}{l}2x-3=4\\2x-3=-4\end{array} \right.\)\(⇔\left[ \begin{array}{l}x=\dfrac{7}{2}\\x=-\dfrac{1}{2}\end{array} \right.\) Vậy $S=\{\dfrac{7}{2};-\dfrac{1}{2}\}$ $b, \bigg{(}-\dfrac{1}{3}\bigg{)}^3.x=\dfrac{1}{81}$ $⇔-\dfrac{1}{27}.x=\dfrac{1}{81}$ $⇔x=-\dfrac{1}{3}$ Vậy $S=\{-\dfrac{1}{3}\}$. Bình luận
a, `(2x – 3)² = 16` `=> 2x – 3 = 4 ` hoặc `2x – 3 = – 4` `=> 2x = 7` hoặc`2x = – 1` `=> x = 7/2` hoặc `x=-1/2` b, ` ( -1/3)³ . x = 1/81` `=> ( -1/3)³ . x = (1/3)^4` `=> x = -1/3` Bình luận
CHÚC BẠN HỌC TỐT!!!
Trả lời:
$a, (2x-3)^2=16$
\(⇔\left[ \begin{array}{l}2x-3=4\\2x-3=-4\end{array} \right.\)\(⇔\left[ \begin{array}{l}x=\dfrac{7}{2}\\x=-\dfrac{1}{2}\end{array} \right.\)
Vậy $S=\{\dfrac{7}{2};-\dfrac{1}{2}\}$
$b, \bigg{(}-\dfrac{1}{3}\bigg{)}^3.x=\dfrac{1}{81}$
$⇔-\dfrac{1}{27}.x=\dfrac{1}{81}$
$⇔x=-\dfrac{1}{3}$
Vậy $S=\{-\dfrac{1}{3}\}$.
a, `(2x – 3)² = 16`
`=> 2x – 3 = 4 ` hoặc `2x – 3 = – 4`
`=> 2x = 7` hoặc`2x = – 1`
`=> x = 7/2` hoặc `x=-1/2`
b, ` ( -1/3)³ . x = 1/81`
`=> ( -1/3)³ . x = (1/3)^4`
`=> x = -1/3`