a) 25- (5-x) = -7
(=) 5-x = 25- (-7)
(=) 5-x = 25+ 7
(=) 5-x = 32
(=) x = 5- 32
(=) x = -27
Vậy x= -27
b)\(\dfrac{1}{2}\)+\(\dfrac{2}{3}\): (x-1)=\(\dfrac{3}{4}\)
(=) \(\dfrac{2}{3}\): (x-1)=\(\dfrac{3}{4}\)-\(\dfrac{1}{2}\)
(=) \(\dfrac{2}{3}\): (x-1)= \(\dfrac{3}{4}\)-\(\dfrac{2}{4}\)
(=) \(\dfrac{2}{3}\): (x-1)= \(\dfrac{1}{4}\)
(=) x-1 = \(\dfrac{1}{4}\). \(\dfrac{2}{3}\)
(=) x-1 = \(\dfrac{1}{6}\)
(=) x = \(\dfrac{1}{6}\)+1
(=) x = \(1\dfrac{1}{6}\)
Vậy x= \(1\dfrac{1}{6}\)
c) \(\dfrac{3}{7}\)+\(\dfrac{4}{7}\)x = \(\dfrac{1}{3}\)
(=) \(\dfrac{4}{7}\)x = \(\dfrac{1}{3}\)-\(\dfrac{3}{7}\)
(=) \(\dfrac{4}{7}\)x = \(\dfrac{7}{21}\)-\(\dfrac{9}{21}\)
(=) \(\dfrac{4}{7}\)x = \(\dfrac{-2}{21}\)
(=) x = \(\dfrac{-2}{21}\): \(\dfrac{4}{7}\)
(=) x = \(\dfrac{-2}{21}\).\(\dfrac{7}{4}\)
(=) x = \(\dfrac{-1}{6}\)
Vậy x= \(\dfrac{-1}{6}\)
d) (2x+1).(x-\(\dfrac{1}{7}\)) = 0
*chỗ này bn tự lập luận nha mik ko bt lập luận
TH1: 2x+1 = 0
(=) 2x = 0-1
(=) 2x = -1
(=) x = -1: 2
(=) x = \(\dfrac{-1}{2}\)
TH2 : x- \(\dfrac{1}{7}\)= 0
(=) x = 0+\(\dfrac{1}{7}\)
(=) x = \(\dfrac{1}{7}\)
Vậy x= \(\dfrac{-1}{2}\) hoặc \(\dfrac{1}{7}\)
P/s :Dấu (=) (tương đương) bn ko ghi cx dc nha
a) 25- (5-x) = -7
(=) 5-x = 25- (-7)
(=) 5-x = 25+ 7
(=) 5-x = 32
(=) x = 5- 32
(=) x = -27
Vậy x= -27
b)\(\dfrac{1}{2}\)+\(\dfrac{2}{3}\): (x-1)=\(\dfrac{3}{4}\)
(=) \(\dfrac{2}{3}\): (x-1)=\(\dfrac{3}{4}\)-\(\dfrac{1}{2}\)
(=) \(\dfrac{2}{3}\): (x-1)= \(\dfrac{3}{4}\)-\(\dfrac{2}{4}\)
(=) \(\dfrac{2}{3}\): (x-1)= \(\dfrac{1}{4}\)
(=) x-1 = \(\dfrac{1}{4}\). \(\dfrac{2}{3}\)
(=) x-1 = \(\dfrac{1}{6}\)
(=) x = \(\dfrac{1}{6}\)+1
(=) x = \(1\dfrac{1}{6}\)
Vậy x= \(1\dfrac{1}{6}\)
c) \(\dfrac{3}{7}\)+\(\dfrac{4}{7}\)x = \(\dfrac{1}{3}\)
(=) \(\dfrac{4}{7}\)x = \(\dfrac{1}{3}\)-\(\dfrac{3}{7}\)
(=) \(\dfrac{4}{7}\)x = \(\dfrac{7}{21}\)-\(\dfrac{9}{21}\)
(=) \(\dfrac{4}{7}\)x = \(\dfrac{-2}{21}\)
(=) x = \(\dfrac{-2}{21}\): \(\dfrac{4}{7}\)
(=) x = \(\dfrac{-2}{21}\).\(\dfrac{7}{4}\)
(=) x = \(\dfrac{-1}{6}\)
Vậy x= \(\dfrac{-1}{6}\)
d) (2x+1).(x-\(\dfrac{1}{7}\)) = 0
*chỗ này bn tự lập luận nha mik ko bt lập luận
TH1: 2x+1 = 0
(=) 2x = 0-1
(=) 2x = -1
(=) x = -1: 2
(=) x = \(\dfrac{-1}{2}\)
TH2 : x- \(\dfrac{1}{7}\)= 0
(=) x = 0+\(\dfrac{1}{7}\)
(=) x = \(\dfrac{1}{7}\)
Vậy x= \(\dfrac{-1}{2}\) hoặc \(\dfrac{1}{7}\)
P/s :Dấu (=) (tương đương) bn ko ghi cx dc nha
a) 25- (5-x) = -7
(=) 5-x = 25- (-7)
(=) 5-x = 25+ 7
(=) 5-x = 32
(=) x = 5- 32
(=) x = -27
Vậy x= -27
b)\(\dfrac{1}{2}\)+\(\dfrac{2}{3}\): (x-1)=\(\dfrac{3}{4}\)
(=) \(\dfrac{2}{3}\): (x-1)=\(\dfrac{3}{4}\)-\(\dfrac{1}{2}\)
(=) \(\dfrac{2}{3}\): (x-1)= \(\dfrac{3}{4}\)-\(\dfrac{2}{4}\)
(=) \(\dfrac{2}{3}\): (x-1)= \(\dfrac{1}{4}\)
(=) x-1 = \(\dfrac{1}{4}\). \(\dfrac{2}{3}\)
(=) x-1 = \(\dfrac{1}{6}\)
(=) x = \(\dfrac{1}{6}\)+1
(=) x = \(1\dfrac{1}{6}\)
Vậy x= \(1\dfrac{1}{6}\)
c) \(\dfrac{3}{7}\)+\(\dfrac{4}{7}\)x = \(\dfrac{1}{3}\)
(=) \(\dfrac{4}{7}\)x = \(\dfrac{1}{3}\)-\(\dfrac{3}{7}\)
(=) \(\dfrac{4}{7}\)x = \(\dfrac{7}{21}\)-\(\dfrac{9}{21}\)
(=) \(\dfrac{4}{7}\)x = \(\dfrac{-2}{21}\)
(=) x = \(\dfrac{-2}{21}\): \(\dfrac{4}{7}\)
(=) x = \(\dfrac{-2}{21}\).\(\dfrac{7}{4}\)
(=) x = \(\dfrac{-1}{6}\)
Vậy x= \(\dfrac{-1}{6}\)
d) (2x+1).(x-\(\dfrac{1}{7}\)) = 0
*chỗ này bn tự lập luận nha mik ko bt lập luận
TH1: 2x+1 = 0
(=) 2x = 0-1
(=) 2x = -1
(=) x = -1: 2
(=) x = \(\dfrac{-1}{2}\)
TH2 : x- \(\dfrac{1}{7}\)= 0
(=) x = 0+\(\dfrac{1}{7}\)
(=) x = \(\dfrac{1}{7}\)
Vậy x= \(\dfrac{-1}{2}\) hoặc \(\dfrac{1}{7}\)
P/s :Dấu (=) (tương đương) bn ko ghi cx dc nha
do máy mik bị lag nên bình luận 3 lần á chứ mik ko spam đâu nha mik xóa r nhưng ko dc thông cảm nhe