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mình viết đáp án luôn nhé
a,x=845/528
b,-7/5
c,-47/140
d,43/1710
chúc bạn làm bài thành công nhe!!@
các bạn nhớ chọn k đúng cho mình nhé
a; - \(\dfrac{10}{13}\) + \(\dfrac{5}{17}\) - \(\dfrac{3}{13}\) + \(\dfrac{12}{17}\) - \(\dfrac{11}{20}\)
= - (\(\dfrac{10}{13}\) + \(\dfrac{3}{13}\)) + (\(\dfrac{5}{17}\) + \(\dfrac{12}{17}\)) - \(\dfrac{11}{20}\)
= - 1 + 1 - \(\dfrac{11}{20}\)
= 0 - \(\dfrac{11}{20}\)
= - \(\dfrac{11}{20}\)
b; \(\dfrac{3}{4}\) + \(\dfrac{-5}{6}\) - \(\dfrac{11}{-12}\)
= \(\dfrac{9}{12}\) - \(\dfrac{10}{12}\) + \(\dfrac{11}{12}\)
= \(\dfrac{10}{12}\)
= \(\dfrac{5}{6}\)
c; [13.\(\dfrac{4}{9}\) + 2.\(\dfrac{1}{9}\)] - 3.\(\dfrac{4}{9}\)
= [\(\dfrac{52}{9}\) + \(\dfrac{2}{9}\)] - \(\dfrac{4}{3}\)
= \(\dfrac{54}{9}\) - \(\dfrac{4}{3}\)
= \(\dfrac{14}{3}\)
a, \(3\left(x-1\right)-\left(2x+3\right)=5\)
\(\Rightarrow3x-3-2x-3=5\)
\(\Rightarrow x-6=5\)
\(\Rightarrow x=11\)
b, \(\frac{6}{13}=\frac{x}{7}\)
\(\Rightarrow x=\frac{6}{13}.7\)
\(\Rightarrow x=\frac{42}{13}\)
c, \(|x|=4\)
\(\Rightarrow x=4\)hoặc \(x=-4\)
d,, \(|x-2|+5=10\)
\(Th1:x-2>0\)
\(\Rightarrow x-2+5=10\)
\(\Rightarrow x+3=10\)
\(\Rightarrow x=7\)
\(Th2;x-2< 0\)
\(\Rightarrow2-x+5=10\)
\(\Rightarrow7-x=10\)
\(\Rightarrow x=-3\)
e, \(3|x-1|-6=9\)
\(Th1:x-1>0\)
\(\Rightarrow3\left(x-1\right)-6=9\)
\(\Rightarrow3x-3-6=9\)
\(\Rightarrow3x-9=9\)
\(\Rightarrow3x=18\)
\(\Rightarrow x=6\)
\(Th2:x-1< 0\)
\(\Rightarrow3\left(1-x\right)-6=9\)
\(\Rightarrow3-3x-6=9\)
\(\Rightarrow-3x-3=9\)
\(\Rightarrow-3x=12\)
\(\Rightarrow x=-4\)
Bài 1:
a)
\(A=\dfrac{-5}{6}\cdot\dfrac{3}{10}\\ =\dfrac{\left(-5\right)\cdot3}{6\cdot10}\\ =\dfrac{-1}{4}\)
b)
\(B=\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{12}\\ =\dfrac{4}{12}-\dfrac{3}{12}+\dfrac{1}{12}\\ =\dfrac{4-3+1}{12}\\ =\dfrac{1}{6}\)
Bài 2:
\(A=\left(\dfrac{-1}{5}\right)\cdot\dfrac{15}{4}+\left|\dfrac{4}{5}-\dfrac{14}{5}\right|:\dfrac{8}{3}\\ =\left(\dfrac{-1}{5}\right)\cdot\dfrac{15}{4}+\left|\dfrac{-10}{5}\right|\cdot\dfrac{3}{8}\\ =\left(\dfrac{-1}{5}\right)\cdot\dfrac{15}{4}+2\cdot\dfrac{3}{8}\\ =\dfrac{-3}{4}+\dfrac{3}{4}\\ =0\)
\(B=\left(\dfrac{-1}{2}\right)^2:1\dfrac{3}{8}+25\%\cdot\dfrac{3}{11}\\ =\left(\dfrac{-1}{2}\right)^2:\dfrac{11}{8}+\dfrac{3}{4}\cdot\dfrac{3}{11}\\ =\dfrac{1}{4}\cdot\dfrac{8}{11}+\dfrac{3}{4}\cdot\dfrac{3}{11}\\ =\dfrac{8}{44}+\dfrac{9}{44}\\ =\dfrac{17}{44}\)
\(C=\dfrac{-8}{5}+0,6+\left|\dfrac{-1}{2}\right|+\dfrac{1}{2}\\ =\dfrac{-8}{5}+\dfrac{3}{5}+\dfrac{1}{2}+\dfrac{1}{2}\\ =\left(\dfrac{-8}{5}+\dfrac{3}{8}\right)+\left(\dfrac{1}{2}+\dfrac{1}{2}\right)\\ =\left(-1\right)+1\\ =0\)
\(D=\dfrac{-5}{9}\cdot\dfrac{2}{13}+\dfrac{-5}{9}:\dfrac{13}{11}+1\dfrac{5}{9}\\ =\dfrac{-5}{9}\cdot\dfrac{2}{13}+\dfrac{-5}{9}\cdot\dfrac{11}{13}+\dfrac{14}{9}\\ =\dfrac{-5}{9}\cdot\left(\dfrac{2}{13}+\dfrac{11}{13}\right)+\dfrac{14}{9}\\ =\dfrac{-5}{9}\cdot1+\dfrac{14}{9}\\ =\dfrac{-5}{9}+\dfrac{14}{9}\\ =1\)
a) = -120
b) = 3 x (-4)
= -12
c) = -8 x 2
= -16
d) = -18 : (-6)
= 3
a, 120
b,-12
c,-16
d,-3
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