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Chịu thôi!Tớ biết cách làm bài nhưng đến phép cuối thì ko so sánh được!Cậu xem lại đầu bài nha!
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\(\frac{1}{4}:\frac{x}{9}=\frac{1}{4}\)
\(\frac{x}{9}=\frac{1}{4}:\frac{1}{4}\)
\(\frac{x}{9}=1\)
\(\Rightarrow x=9\)
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a)
12,5 x 40,7 + 59,3 x12,5
= 12,5 x ( 40,7 + 59,3)
= 12,5 x 100
= 1250
a]
12,5 x 40,7 + 59,3 x 12,5
= 12,5 x [ 40,7 + 59,3]
= 12,5 x 100 = 125
b]
1,9 + 1,8 + 1,7 + 1,6 + 1,5 , 1,4 , 1,3 , 1,2 , 1,1
= [1,9 + 1,1 ] + [1,8 + 1,2 ] + [ 1,7 + 1,3 ] + [1,6 + 1,4 ] + 1,5
= [3 + 3 + 3 + 3 ]+ 1,5
= 12 + 1,5
=13,5
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\(=\frac{4}{3}x\frac{9}{8}x\frac{16}{15}x\frac{25}{24}x...x\frac{100}{99}\)
\(=\frac{2x2x3x3x4x4x5x5x6x6x7x7x8x8x9x9x10x10}{1x3x2x4x3x5x4x6x5x7x6x8x7x9x8x10x9x11}=\frac{2x10}{11}=\frac{20}{11}\)
Lưu Hạ Băng
Ta có : \(1\frac{1}{3}x1\frac{1}{8}x1\frac{1}{15}x1\frac{1}{24}x...x1\frac{1}{99}\)
\(=\frac{4}{3}x\frac{9}{8}x\frac{16}{15}x\frac{25}{24}x...x\frac{100}{99}\)
\(=\frac{2x2}{1x3}x\frac{3x3}{2x4}x\frac{4x4}{3x5}x\frac{5x5}{4x6}x...x\frac{10x10}{9x11}\)
\(=\frac{2x2x3x3x4x4x5x5x...x10x10}{1x3x2x4x3x5x4x6x...x9x11}\)
\(=\frac{\left(2x3x4x5x...x10\right)x\left(2x3x4x5x...x10\right)}{\left(1x2x3x4x...x9\right)x\left(3x4x5x6x...x11\right)}\)
\(=\frac{10x2}{1x11}\)
\(=\frac{20}{11}\)
Chúc bn học tốt !!!
Kb vs mk heg =)) ^^
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\(\frac{x}{5}=\frac{20}{x}\)
Ta có :
x . x = 20 . 5
x2 = 100
=> x = 10 hoặc x = -10
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\(\frac{1}{2}\cdot x+\frac{3}{5}\cdot x=\frac{1}{5}\)
\(\left(\frac{1}{2}+\frac{3}{5}\right)x=\frac{1}{5}\)
\(\frac{11}{10}\cdot x=\frac{1}{5}\)
\(x=\frac{1}{5}:\frac{11}{10}\)
\(x=\frac{2}{11}\)
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\(\frac{46}{52}-\frac{15}{26}=\frac{46}{52}-\frac{30}{52}=\frac{16}{52}=\frac{4}{13}\)
\(\frac{15}{26}+\frac{x}{16}=\frac{46}{52}\)
\(\Leftrightarrow\frac{15}{26}+\frac{x}{16}=\frac{23}{26}\)
\(\Leftrightarrow\frac{x}{16}=\frac{23}{26}-\frac{15}{26}\)
\(\Leftrightarrow\frac{x}{16}=\frac{8}{26}=\frac{4}{13}\)
\(\Rightarrow13x=16\times4\)
\(\Rightarrow x=\frac{64}{13}\)
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a) \(\frac{24}{x}=\frac{3}{5}.\frac{8}{3}\)
\(\frac{24}{x}=\frac{8}{5}\)
\(x=\frac{24.5}{8}\)
\(x=15\)
b) \(2.x=24\frac{1}{4}-3\frac{1}{2}\)
\(2.x=\frac{83}{4}\)
\(x=\frac{83}{8}\)
Câu c, d làm tương tự, đơn giản
40,7 × 6,4 + 46 × 4,07
= 40,7 × 6,4 + 4,6 × 40,7
= 40,7 × (6,4 + 4,6)
= 40,7 × 11
= 447,7
thanks ban