Câu `1`:

`a)(2/11)^4 . (-11/4)^4`

`=(-1/2)^4`

`=1/(16)`

`b)(-3/4+2/5) : 3/7+(3/5+(-1)/4) : 3/7`

`=(-3/4+2/5) . 7/3+(3/5+(-1)/4) . 7/3`

`=7/3.[(-3/4)+2/5+3/5+(-1/4)]`

`=7/3.[(-3/4+(-1)/4)+(2/5+3/5)]`

`=7/3. (-4/4)+5/5`

`=7/3. [(-1)+1]`

`=(-7/3) . 0`

`=0`

Câu `2`:

`a)1/3+1/2 : x=-4`

          `1/2 : x=(-4) - 1/3`

          `1/2 : x=(-13)/3`

                  `x=1/2 : (-13)/3`

                  `x=-3/(26)`

Vậy `x=-3/(26)`

`b)|x-1|-3=1/4`

   `|x-1|=1/4 + 3`

   `|x-1|=(13)/4`

`⇒`\(\left[ \begin{array}{l}x-1=\dfrac{13}{4}\\x-1=\dfrac{-13}{4}\end{array} \right.\) 

`⇒`\(\left[ \begin{array}{l}x=\dfrac{13}{4} + 1\\x=\dfrac{-13}{4} + 1\end{array} \right.\) 

`⇒`\(\left[ \begin{array}{l}x=\dfrac{17}{4}\\x=\dfrac{-9}{4}\end{array} \right.\) 

Vậy `x=17/4` hoặc `x=-9/4`

Đáp án:

Câu `1`

`a,`

`(2/11)^4 × ( (-11)/4)^4`

`= (2/11 × (-11)/4)^4`

`= ( (-1)/2)^4`

`= 1/16`

`b,`

`( (-3)/4 + 2/5) ÷ 3/7   + (3/5  + (-1)/4 ) ÷ 3/7`

`= ( (-3)/4 + 2/5) × 7/3 + (3/5 + (-1)/4) × 7/3`

`= 7/3 × [ ( (-3)/4 + 2/5) + (3/5 + (-1)/4)`

`= 7/3 × [(-3)/4 + 2/5 + 3/5 + (-1)/4]`

`= 7/3 × [ ( (-3)/4 + (-1)/4) + (2/5 + 3/5)]`

`= 7/3 × [-1 + 1]`

`= 7/3 × 0`

`= 0`

$\\$

Câu `2`

`a,`

`1/3 + 1/2 ÷ x=  -4`

`-> 1/2 ÷ x = -4 - 1/3`

`-> 1/2 ÷ x = (-13)/3`

`-> x = 1/2 ÷ (-13)/3`

`-> x = 1/2 × (-3)/13`

`-> x=  (-3)/26`

Vậy `x = (-3)/26`

`b,`

`|x - 1| - 3 = 1/4`

`-> |x  -1| =1/4 + 3`

`-> |x - 1| =13/4`

`->` \(\left[ \begin{array}{l}x-1=\dfrac{13}{4}\\x-1=\dfrac{-13}{4}\end{array} \right.\) 

`->` \(\left[ \begin{array}{l}x=\dfrac{13}{4}+1\\x=\dfrac{-13}{4}+1\end{array} \right.\) 

`->` \(\left[ \begin{array}{l}x=\dfrac{17}{4}\\x=\dfrac{-9}{4}\end{array} \right.\) 

Vậy `x=17/4` hoặc `x=(-9)/4`