Đáp án:
Theo y/c Tus:
Phần 1: `c)` `1/2`
Phần 2: `b)` `±1` `c)` `9/4` hoặc `3/4`
Phần 3: `a)` `25/81` `b)` `4/5` `c)` `-1/4` hoặc `x=-3/4`
Giải thích các bước giải:
PHẦN 1:
`c)` `(x-1/2)^2=0`
`⇒ x-1/2 =0`
`⇒ x =1/2`
Vậy `x=1/2`
PHẦN 2:
`b)` `x:((-5)/9)^8=((-9)/5)^8`
`⇒ x =((-9)/5)^8*((-5)/9)^8`
`⇒ x =((-9)/5*(-5)/9)^8`
`⇒ x =(±1)^8`
`⇒ x =±1`
Vậy `x=±1`
`c)` `(x-3/2)^2=9/16`
`⇒(x-3/2)^2=(±3/4)^2`
`⇒x-3/2 =±3/4`
`⇒`\(\left[ \begin{array}{l}x-\dfrac{3}{2}=\dfrac{3}{4}\\x-\dfrac{3}{2}=-\dfrac{3}{4}\end{array} \right.\)`⇒`\(\left[ \begin{array}{l}x=\dfrac{3}{2}+\dfrac{3}{4}\\x=\dfrac{3}{2}-\dfrac{3}{4}\end{array} \right.\)`⇒`\(\left[ \begin{array}{l}x=\dfrac{6+3}{4}\\x=\dfrac{6-3}{4}\end{array} \right.\) `⇒`\(\left[ \begin{array}{l}x=\dfrac{9}{4}\\x=\dfrac{3}{4}\end{array} \right.\)
Vậy `x=9/4` hoặc `x=3/4`
PHẦN 3:
`a)` `((-5)/9)^10:x=((-5)/9)^8`
`⇒ x=((-5)/9)^10:((-5)/9)^8`
`⇒ x=((-5)/9)^(10-8)`
`⇒ x=((-5)/9)^2`
`⇒ x=25/81`
Vậy `x=25/81`
`b)` `(4/5)^5:x=((-4)/5)^4`
`⇒ x=(4/5)^5:(4/5)^4`
`⇒ x=(4/5)^(5-4)`
`⇒ x=4/5`
Vậy `x=4/5`
`c)` `(x+1/2)^2=1/16`
`⇒ (x+1/2)^2=(±1/4)^2`
`⇒`\(\left[ \begin{array}{l}x+\dfrac{1}{2}=\dfrac{1}{4}\\x+\dfrac{1}{2}=-\dfrac{1}{4}\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l}x=\dfrac{1}{4}-\dfrac{1}{2}\\x=-\dfrac{1}{4}-\dfrac{1}{2}\end{array} \right.\)`⇒`\(\left[ \begin{array}{l}x=\dfrac{1-2}{4}\\x=-\dfrac{1+2}{4}\end{array} \right.\) `⇒`\(\left[ \begin{array}{l}x=-\dfrac{1}{4}\\x=-\dfrac{3}{4}\end{array} \right.\)
Vậy `x=-1/4` hoặc `x=-3/4`
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