Đáp án:
`a,`
`x ÷ 4 1/3 = -2,5`
`-> x ÷ 13/3 = -2,5`
`-> x = -2,5 × 13/3`
`-> x= (-65)/6`
Vậy `x = (-65)/6`
`b,`
`1/2x - 2/3x = 7/12`
`-> (1/2 - 2/3)x = 7/12`
`-> (-1)/6x = 7/12`
`-> x = 7/12 ÷ (-1)/6`
`-> x = (-7)/2`
Vậy `x = (-7)/2`
`c,`
`( (3x)/7 + 1) ÷ (-4) = (-1)/28`
`-> (3x)/7 + 1 = (-1)/28 × (-4)`
`-> (3x)/7 + 1 = 1/7`
`-> (3x)/7 = 1/7 - 1`
`-> (3x)/7 = (-6)/7`
`-> 3x = 7 × (-6)/7`
`-> 3x = -6`
`-> x = -6 ÷ 3`
`-> x = -2`
Vậy `x = -2`
`d,`
`2/3 + 1/3 × (2x - 1) = -5`
`-> 1/3 (2x - 1) = -5 - 2/3`
`-> 1/3 (2x - 1) = (-17)/3`
`-> 2x - 1 = (-17)/3 ÷ 1/3`
`-> 2x - 1 = -17`
`-> 2x = -16`
`-> x = -8`
Vậy `x = -8`
`e,`
`2/5 - 1/4 ÷ x = -25%`
`-> 1/4 ÷ x = 2/5 - (-25%)`
`-> 1/4 ÷ x = 13/20`
`-> x = 1/4 ÷ 13/20`
`-> x = 5/13`
Vậy `x= 5/13`
`g,`
`|2x - 1| =5`
`->` \(\left[ \begin{array}{l}2x-1=5\\2x-1=-5\end{array} \right.\)
`->` \(\left[ \begin{array}{l}2x=6\\2x=-4\end{array} \right.\)
`->` \(\left[ \begin{array}{l}x=3\\x=-2\end{array} \right.\)
Vậy `x = 3` hoặc `x = -2`
`f,`
`(3x - 1) (-1/2x + 5) = 0`
`->` \(\left[ \begin{array}{l}3x-1=0\\ \dfrac{-1}{2}x+5=0\end{array} \right.\)
`->` \(\left[ \begin{array}{l}3x=1\\ \dfrac{-1}{2}x=-5\end{array} \right.\)
`->` \(\left[ \begin{array}{l}x=\dfrac{1}{3}\\x=-10\end{array} \right.\)
Vậy `x = 1/3` hoặc `x = -10`
`g,`
`(-3 1/2 -2x) ÷ 3 2/3 = 15/22`
`-> (-7/2 - 2x) ÷ 11/3 = 15/22`
`-> -7/2 - 2x = 5/2`
`->2x = -7/2 - 5/2`
`-> 2x = -6`
`-> x = -3`
Vậy `x= -3`
