4/9+2/9+2/9=....x1/9
Những câu hỏi liên quan
tính bằng 2 cách:
a).(1/5+3/5)x1/4
(1/5+3/5)x1/4
b).(7/9-2/9)x3/2
(7/9-2/9)x3/2
c).(11/13-9/13)x39/21
(11/13-9/13)x39/21
ai làm day du 2 cach tung cau minh tick.luu y:day du loi giai
a) \(\left(\frac{1}{5}+\frac{3}{5}\right)\times\frac{1}{4}\)
\(=\frac{4}{5}\times\frac{1}{4}\)
\(=\frac{4}{20}=\frac{1}{5}\)
\(\left(\frac{1}{5}+\frac{3}{5}\right)\times\frac{1}{4}=\frac{1}{5}\times\frac{1}{4}+\frac{3}{5}\times\frac{1}{4}\)
\(=\frac{1}{20}+\frac{3}{20}\)
\(=\frac{4}{20}=\frac{1}{5}\)
b) \(\left(\frac{7}{9}-\frac{2}{9}\right)\times\frac{3}{2}\)
\(=\frac{5}{9}\times\frac{3}{2}\)
\(=\frac{15}{18}=\frac{5}{6}\)
\(\left(\frac{7}{9}-\frac{2}{9}\right)\times\frac{3}{2}=\frac{7}{9}\times\frac{3}{2}-\frac{2}{9}\times\frac{3}{2}\)
\(=\frac{21}{18}-\frac{6}{18}\)
\(=\frac{15}{18}=\frac{5}{6}\)
c) \(\left(\frac{11}{13}-\frac{9}{13}\right)\times\frac{39}{21}\)
\(=\frac{2}{13}\times\frac{39}{21}\)
\(=\frac{78}{273}=\frac{2}{7}\)
\(\left(\frac{11}{13}-\frac{9}{13}\right)\times\frac{39}{21}=\frac{11}{13}\times\frac{39}{21}-\frac{9}{13}\times\frac{39}{21}\)
\(=\frac{429}{273}-\frac{351}{273}\)
\(=\frac{78}{273}=\frac{2}{7}\)
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a,\(\left(\frac{1}{5}+\frac{3}{5}\right)x\frac{1}{4}\)
=\(\frac{4}{5}x\frac{1}{4}\)
=\(\frac{4}{20}\)
=\(\frac{1}{5}\)
,\(\left(\frac{1}{5}+\frac{3}{5}\right)x\frac{1}{4}\)
=\(\frac{4}{5}x\frac{1}{4}\)
=\(\frac{4x1}{5x4}\)
=\(\frac{1x1}{5x1}\)
=\(\frac{1}{5}\)
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\(\dfrac{4}{9}+\dfrac{5}{8}\)=
\(\dfrac{6}{10}+\dfrac{9}{2}=\)
\(\dfrac{10}{2}-\dfrac{5}{2}=\)
\(\dfrac{8}{8}x1=\)
\(\dfrac{4}{9}+\dfrac{5}{8}\)=\(\dfrac{32}{72}+\dfrac{45}{72}=\dfrac{77}{72}\)
\(\dfrac{6}{10}+\dfrac{9}{2}=\dfrac{6}{10}+\dfrac{45}{10}=\dfrac{51}{10}\)
\(\dfrac{10}{2}-\dfrac{5}{2}=\dfrac{5}{2}\)
\(\dfrac{8}{8}x1=\dfrac{8}{8}x\dfrac{1}{1}=\dfrac{8}{8}\)
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9 + 9 + 9 ............. x 9 x 2 x 0x1 x1 x999999999
(9/2-2x)x1 4/7=11/14
\(\left(\dfrac{9}{2}-2x\right)\cdot1\dfrac{4}{7}=\dfrac{11}{14}\\ \\\\ \Rightarrow\left(\dfrac{9}{2}-2x\right)\cdot\dfrac{11}{7}=\dfrac{11}{14}\\ \\\\ \Rightarrow\dfrac{9}{2}-2x=\dfrac{11}{14}:\dfrac{11}{7}=\dfrac{11}{14}\cdot\dfrac{7}{11}=\dfrac{1}{2}\\ \\ \\ \Rightarrow2x=\dfrac{9}{2}-\dfrac{1}{2}=\dfrac{8}{2}=4\\ \\ \\ \Rightarrow x=4:2=2\)
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(\(\dfrac{9}{2}\) - 2\(x\)) \(\times\) 1\(\dfrac{4}{7}\) = \(\dfrac{11}{14}\)
( \(\dfrac{9}{2}\) - 2\(x\)) \(\times\) \(\dfrac{11}{7}\) = \(\dfrac{11}{14}\)
\(\dfrac{9}{2}\) - 2\(x\) = \(\dfrac{11}{14}\) : \(\dfrac{11}{7}\)
\(\dfrac{9}{2}\) - 2\(x\) = \(\dfrac{1}{2}\)
2\(x\) = \(\dfrac{9}{2}\) - \(\dfrac{1}{2}\)
2\(x\) = 4
\(x\) = 4 : 2
\(x\) = 2
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Xem thêm câu trả lời
Tính giá trị biểu thức:
(4/9-2/7)x1/2
=........
Giúp mik câu này mik đag cần gấp
Tính :
1)3/5 x1/7 +3/5 x6/7 -3/5
2)6/7 x4/9 + 6/7 x5/9 + 6/7
3) 9/13 x 7/12 + 9/13 x 5/12 - 9/13
4) 4/13 x5/12 +4/13 x 7/12 - 4/13
1) = \(\frac{3}{5}\)
2) =\(\frac{6}{7}\)
3)\(\frac{9}{13}\)
4)\(\frac{4}{13}\)
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Cho pt x^2-mx+2m-4=0.tìm m để pt có 2 nghiệm x1,x2 chứng minh
A,x1^2 +x2^2 =13
B,x1^3 +x2^3 =9
Δ=(-m)^2-4(2m-4)
=m^2-8m+16=(m-4)^2>=0
=>Phương trình luôn có hai nghiệm
a: x1^2+x2^2=13
=>(x1+x2)^2-2x1x2=13
=>m^2-2(2m-4)-13=0
=>m^2-4m-5=0
=>m=5 hoặc m=-1
b: x1^3+x2^3=9
=>(x1+x2)^3-3*x1x2(x1+x2)=9
=>m^3-3*(2m-4)*m=9
=>m^3-6m^2+12m-9=0
=>m=3
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tim x1,x2,x3,...,x9 biết
x1-1/9=x2-2/8=x3-3/7=...=x9-9/1 va x1+x2+x3+...+x9=90
tìm m để phương trình có 2 nghiệm x1,x2 sao cho biểu thức A=(x1^2-9)(x2^2-4) đạt gtln