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a.
31,5 – x = (18,6 – 12,3) : 3
31,5 - x = 2,1
x = 31,5 - 2,1
x = 29,4
b.
???
\(\frac{17,8.3,7-7,8.4,8+5,7.17,8-4,6.7,8}{11,2+12,3+13,4-12,6-11,5-10,4}\)
\(=\frac{17,8\left(3,7+5,7\right)-7,8\left(4,8+4,6\right)}{\left(13,4-12,6\right)+\left(12,3-11,5\right)+\left(11,2-10,4\right)}\)
\(=\frac{17,8.9,4-7,8.9,4}{0,8+0,8+0,8}\)
\(=119,1\)
a: \(\Leftrightarrow x\cdot12.3=123\)
=>x=10
b: \(\dfrac{3x-0.8}{x}+14.5=15\)
\(\Leftrightarrow\dfrac{3x-0.8}{x}=0.5\)
\(\Leftrightarrow3x-0.8=0.5x\)
=>2,5x=0,8
hay x=8/25
c: \(\Leftrightarrow12.5\cdot x=5.58-4.85=0.73\)
hay x=73/1250
\(a,12,3\cdot4,7+5,3\cdot12,3-1,4\cdot7,5+7,5\cdot5,4\)
\(=12,3\cdot\left(4,7+5,3\right)-7,5\cdot\left(1,4+5,4\right)\)
\(=12,3\cdot10-7,5\cdot6,8\)
\(=123-51\)
\(=72.\)
\(b,3\cdot x-1=\frac{3}{4}:\frac{15}{16}\)
\(\Leftrightarrow3\cdot x-1=\frac{3}{4}\cdot\frac{16}{15}\)
\(\Leftrightarrow3\cdot x-1=\frac{4}{5}\)
\(\Leftrightarrow3\cdot x=\frac{4}{5}+1\)
\(\Leftrightarrow3\cdot x=\frac{9}{5}\)
\(\Leftrightarrow x=\frac{9}{5}\div3\)
\(\Leftrightarrow x=\frac{9}{5}\cdot\frac{1}{3}\)
\(\Leftrightarrow x=\frac{3}{5}\)
a) \(12,3\times4,7+5,3\times12,3-1,4\times7,5+7,5\times5,4\)
\(=12,3\times\left(4,7+5,3\right)+7,5\times\left(5,4-1,4\right)\)
\(=12,3\times10+7,5\times4\)
\(=123+30\)
\(=153\)
b) \(3.x-1=\frac{3}{4}:\frac{15}{16}\)
\(\Rightarrow3.x-1=\frac{4}{5}\)
\(\Rightarrow3.x=\frac{9}{5}\Rightarrow x=\frac{3}{5}\)
1) \(16,2\times3,7+5,7\times16,2-7,8\times4,8-4,6\times7,8\)
\(=16,2.\left(3,7\times5,7\right)-7,8.\left(4,8\times4,6\right)\)
\(=16,2.9,4-7,8.9,4\)
\(=9,4.\left(16,2-7,8\right)\)
\(=9,4.8,4=78,96\)
2) \(11,2+12,3+13,4-12,6-11,5-10,4\)
\(=\left(11,2-10,4\right)+\left(12,3-11,5\right)+\left(13,4-12,6\right)\)
\(=0,8+0,8+0,8\)
\(=0,8.3=2,4\)
1) 16,2×3,7+5,7×16,2−7,8×4,8−4,6×7,816,2×3,7+5,7×16,2−7,8×4,8−4,6×7,8
=16,2.(3,7×5,7)−7,8.(4,8×4,6)=16,2.(3,7×5,7)−7,8.(4,8×4,6)
=16,2.9,4−7,8.9,4=16,2.9,4−7,8.9,4
=9,4.(16,2−7,8)=9,4.(16,2−7,8)
=9,4.8,4=78,96=9,4.8,4=78,96
2) 11,2+12,3+13,4−12,6−11,5−10,411,2+12,3+13,4−12,6−11,5−10,4
=(11,2−10,4)+(12,3−11,5)+(13,4−12,6)=(11,2−10,4)+(12,3−11,5)+(13,4−12,6)
=0,8+0,8+0,8=0,8+0,8+0,8
=0,8.3=2,4
1) \(31,5\cdot0,1+3x=7,65\)
\(\Leftrightarrow3,15+3x=7,65\)
\(\Leftrightarrow3x=4,5\)
\(\Leftrightarrow x=1,5\)
b)\(\frac{3}{8}+\left(x-\frac{5}{24}\right):\frac{2}{3}=1\)
\(\Leftrightarrow\left(x-\frac{5}{24}\right):\frac{2}{3}=\frac{5}{8}\)
\(\Leftrightarrow x-\frac{5}{24}=\frac{5}{12}\)
\(\Leftrightarrow x=\frac{5}{8}\)
1. \(31,5.0,1+3x=7,65\)
\(\Leftrightarrow3,15+3x=7,65\)
\(\Leftrightarrow3x=4,5\)
\(\Leftrightarrow x=1,5\)
2. \(\frac{3}{8}+\left(x-\frac{5}{24}\right):\frac{2}{3}=1\)
\(\Leftrightarrow\left(x-\frac{5}{24}\right):\frac{2}{3}=\frac{5}{8}\)
\(\Leftrightarrow x-\frac{5}{24}=\frac{5}{8}.\frac{2}{3}\)
\(\Leftrightarrow x-\frac{5}{24}=\frac{5}{12}\)
\(\Leftrightarrow x=\frac{5}{8}\)
a) 31,5 - X = 2.1
X = 31,5 - 2,1
X = 29.4
b) X . 12,5 = 111
X = 111 : 12,5
X = 8.88
a)\(x=31,5-\left[\left(18,6-12,3\right):3\right]=31,5-2,1=29,4\)
b)\(x=\left[\left(32,6-10,4\right).5\right]=11112,5=8,88\)