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\(x-\frac{1}{5}=-2\frac{1}{3}\)
\(x-\frac{1}{5}=\frac{-7}{3}\)
\(x=\frac{-7}{3}+\frac{1}{5}\)
\(x=\frac{-32}{15}\)
~ Hok tốt ~
Câu 1:
A = \(\dfrac{-7}{12}+\dfrac{11}{8}-\dfrac{5}{9}=\dfrac{-42}{72}+\dfrac{99}{72}-\dfrac{40}{72}=\dfrac{-42+99-40}{72}=\dfrac{17}{72}\)
\(B=\dfrac{1}{7}-\dfrac{8}{7}:8-3:\dfrac{3}{4}.2^2=\dfrac{1}{7}-\dfrac{8}{7}.\dfrac{1}{8}-3.\dfrac{4}{3}.4=\dfrac{1}{7}-\dfrac{1}{7}-16=0-16=-16\)
\(C=1,4.\dfrac{15}{49}-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):\dfrac{11}{5}=\dfrac{7}{5}.\dfrac{15}{49}-\dfrac{22}{15}.\dfrac{5}{11}=\dfrac{3}{7}-\dfrac{2}{3}=\dfrac{9-14}{21}=-\dfrac{5}{21}\)
Vậy A=\(\dfrac{17}{72};B=-16;C=\dfrac{-5}{21}\)
Câu 2:
a. \(\dfrac{-11x}{12}+\dfrac{3}{4}=-\dfrac{1}{6}\)
\(\Rightarrow\dfrac{-11x}{12}=-\dfrac{1}{6}-\dfrac{3}{4}\)
\(\Rightarrow\dfrac{-11x}{12}=\dfrac{-2}{12}-\dfrac{9}{12}\)
\(\Rightarrow\dfrac{-11x}{12}=\dfrac{-11}{12}\)
\(\Rightarrow-11x=\dfrac{-11.12}{12}\)
\(\Rightarrow-11x=-11\Rightarrow x=1\)
Vậy x=1
b. \(3-(\dfrac{1}{6}-x).\dfrac{2}{3}=\dfrac{2}{3}\Rightarrow3-\left(\dfrac{1}{6}-x\right)=1\)
\(\Rightarrow-(\dfrac{1}{6}-x)=1-3\Rightarrow\dfrac{1}{6}+x=-2\)
\(\Rightarrow x=2-\dfrac{1}{6}\Rightarrow x=\dfrac{11}{6}\)
Vậy x = \(\dfrac{11}{6}\)
Câu 4:
Ta có: \(\dfrac{1}{2.3}=\dfrac{1}{6}\)
\(\dfrac{1}{2}-\dfrac{1}{3}=\dfrac{3}{6}-\dfrac{2}{6}=\dfrac{1}{6}\)
\(\Rightarrow\dfrac{1}{2.3}=\dfrac{1}{2}-\dfrac{1}{3}\)
a) 7(x - 5) + 2 = 51
\(\Leftrightarrow\) 7(x - 5) = 51 - 2
\(\Leftrightarrow\) 7(x - 5) = 49
\(\Leftrightarrow\) x - 5 = 49 : 7
\(\Leftrightarrow\) x - 5 = 7
\(\Leftrightarrow\) x = 7 + 5
\(\Leftrightarrow\) x = 12.
Vậy x = 12.
k) 2412 : (3x + 147) = |-38| + (-26)
\(\Leftrightarrow\) 2412 : (3x + 147)= 38 + (-26)
\(\Leftrightarrow\) 2412 : (3x + 147)= 12
\(\Leftrightarrow\) 3x + 147 = 2412 : 12
\(\Leftrightarrow\) 3x + 147 = 201
\(\Leftrightarrow\) 3x = 201 - 147
\(\Leftrightarrow\) 3x = 54
\(\Leftrightarrow\) x = 54 : 3
\(\Leftrightarrow\) x = 18.
Vậy x = 18.
I) 4824 : (4x + 137) = |-59| + (-35)
\(\Leftrightarrow\) 4824 :(4x + 137) = 59 + (-35)
\(\Leftrightarrow\) 4824 :(4x + 137) = 24
\(\Leftrightarrow\) 4x + 137 = 4824 : 24
\(\Leftrightarrow\) 4x + 137 = 201
\(\Leftrightarrow\) 4x = 201 - 137
\(\Leftrightarrow\) 4x = 64
\(\Leftrightarrow\) x = 64 : 4
\(\Leftrightarrow\) x = 16.
Vậy x = 16.
c) |-123| - 5(x - 3) = (-28) + 66
\(\Leftrightarrow\) 123 - 5(x - 3) = 38
\(\Leftrightarrow\) 5(x - 3) = 123 - 38
\(\Leftrightarrow\) 5(x - 3) = 85
\(\Leftrightarrow\) x - 3 = 85 : 5
\(\Leftrightarrow\) x - 3 = 17
\(\Leftrightarrow\) x = 17 + 3
\(\Leftrightarrow\) x = 20.
Vậy x = 20.
m) 7x - 4 . 6 = 2058
\(\Leftrightarrow\) 7x - 24 = 2058
\(\Leftrightarrow\) 7x = 2058 + 24
\(\Leftrightarrow\) 7x = 2082
\(\Leftrightarrow\) x = 2082 : 7
\(\Leftrightarrow\) x = \(\frac{2058}{7}\).
Vậy x = \(\frac{2058}{7}\).
Phần b) ra phân số nên mình để mai làm và cả những bài còn lại nữa.
Chúc bạn học tốt !!!
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Gợi ý thui :v
Giải hơi dài dòng :v
\(a,x-\frac{1}{5}=-2\frac{1}{3}\)
\(\Rightarrow x-\frac{1}{5}=-\frac{7}{3}\)
\(\Leftrightarrow x=-\frac{7}{3}+\frac{1}{5}=-\frac{32}{15}\)
\(b,\frac{1}{4}+\frac{3}{4}:x=\frac{1}{2}\)
\(\Rightarrow\frac{3}{4}:x=\frac{1}{2}-\frac{1}{4}\)
\(\Rightarrow\frac{3}{4}x=\frac{1}{4}\Leftrightarrow x=\frac{1}{3}\)
c, Tự làm
a. x - 1/5 = -2 1/3
x - 1/5 = -7/3
x = -2 2/15
b. 1/4 + 3/4 : x = 1/2
3/4 : x = 1/2 - 1/4
3/4 : x = 1/4
x = 3/4 x 4
x = 3
c. -0,75x + 8/11x = 23/44
(-3/4 + 8/11)x = 23/44
-1/44x = 23/44
x = -23