a) (2x+3)2 = 9/121; b) (3x-1)3 = (-8)/27 19/07/2021 Bởi Maria a) (2x+3)2 = 9/121; b) (3x-1)3 = (-8)/27
Đáp án: Giải thích các bước giải: a) `(2x+3)^2 = 9/121` `⇔ (2x+3)^2=(3/11)^2` `⇔` \(\left[ \begin{array}{l}2x+3=\dfrac{3}{11}\\2x+3=-\dfrac{3}{11}\end{array} \right.\) `⇔` \(\left[ \begin{array}{l}x=-\dfrac{15}{11}\\x=-\dfrac{18}{11}\end{array} \right.\) b) `(3x-1)^3 = (-8)/27` `⇔ (3x-1)^3=(-2/3)^3` `⇔ 3x-1=-2/3` `⇔ 3x=1/3` `⇔ x=1/9` Bình luận
a) $(2x+3)^2=\dfrac{9}{121}$ \(↔\left[ \begin{array}{l}2x+3=\dfrac{3}{11}\\2x+3=-\dfrac{3}{11}\end{array} \right.\) \(↔\left[ \begin{array}{l}2x=-\dfrac{30}{11}\\2x=-\dfrac{36}{11}\end{array} \right.\) \(↔\left[ \begin{array}{l}x=-\dfrac{15}{11}\\x=-\dfrac{18}{11}\end{array} \right.\) b) $(3x-1)^3=\dfrac{-8}{27}$ $↔3x-1=\dfrac{-2}{3}$ $↔3x=-\dfrac{2}{3}+1$ $↔3x=\dfrac{1}{3}$ $↔x=\dfrac{1}{3}:3$ $↔x=\dfrac{1}{9}$ Bình luận
Đáp án:
Giải thích các bước giải:
a) `(2x+3)^2 = 9/121`
`⇔ (2x+3)^2=(3/11)^2`
`⇔` \(\left[ \begin{array}{l}2x+3=\dfrac{3}{11}\\2x+3=-\dfrac{3}{11}\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=-\dfrac{15}{11}\\x=-\dfrac{18}{11}\end{array} \right.\)
b) `(3x-1)^3 = (-8)/27`
`⇔ (3x-1)^3=(-2/3)^3`
`⇔ 3x-1=-2/3`
`⇔ 3x=1/3`
`⇔ x=1/9`
a) $(2x+3)^2=\dfrac{9}{121}$
\(↔\left[ \begin{array}{l}2x+3=\dfrac{3}{11}\\2x+3=-\dfrac{3}{11}\end{array} \right.\)
\(↔\left[ \begin{array}{l}2x=-\dfrac{30}{11}\\2x=-\dfrac{36}{11}\end{array} \right.\)
\(↔\left[ \begin{array}{l}x=-\dfrac{15}{11}\\x=-\dfrac{18}{11}\end{array} \right.\)
b) $(3x-1)^3=\dfrac{-8}{27}$
$↔3x-1=\dfrac{-2}{3}$
$↔3x=-\dfrac{2}{3}+1$
$↔3x=\dfrac{1}{3}$
$↔x=\dfrac{1}{3}:3$
$↔x=\dfrac{1}{9}$