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`
