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\(a.\left(x\times0,25+1999\right)\times2000=2052\times2000\\ \left(x\times0,25+1999\right)\times2000=4104000\\ x\times0,25+1999=4104000:2000\\ x\times0,25+1999=2052\\ x\times0,25=2052-1999\\ x\times0,25=53\\ x=53:0,25\\ x=212\)
\(71+52,5\times4=\frac{x+140}{x}+210\)
\(71+210=\frac{x+140}{x}+210\)
\(=>\frac{x+140}{x}=71\)
\(71=\frac{142}{2}\)\(\Rightarrow x=142-140=2\)
<=> 71=\(\dfrac{x+140}{x}\)
=>71x=x+140
<=>71x-x=140
<=>70x=140
<=>x=2
Vậy x=2
Ta có (x + 1) + (x + 2) + .......... + ( x + 9) = 545
<=> (x + x + x + ....... + x) + ( 1 + 2 + ...... + 9) = 545
<=> 9x + 45 = 545
=> 9x = 500
=> x = 500/9
a) \(\left(x+1\right)+\left(x+4\right)+\left(x+7\right)+...+\left(x+28\right)=155\)
\(\Rightarrow10\times x+\left(1+4+7+...+28\right)=155\)
\(\Rightarrow10\times x+\frac{\left(1+28\right)\times10}{2}=155\)
\(\Rightarrow10\times x+145=155\)
\(\Rightarrow10\times x=10\Rightarrow x=1\)
b)
( 1 + \(\dfrac{2}{5}\)).( 1 + \(\dfrac{2}{7}\) ).( 1 + \(\dfrac{2}{9}\)).( 1 + \(\dfrac{2}{11}\)).....( 1 + \(\dfrac{2}{97}\)).( 1 + \(\dfrac{2}{99}\))
= \(\dfrac{7}{5}\).\(\dfrac{9}{7}\).\(\dfrac{11}{9}\).\(\dfrac{13}{11}\)...\(\dfrac{99}{97}\).\(\dfrac{101}{99}\)
= \(\dfrac{7.9.11.13...99.101}{5.7.9.11...97.99}\)
= \(\dfrac{101}{5}\)
❤ HOK TT ❤
địt mẹ cái thằng ngu hốc cặc
\(\dfrac{x+140}{x}\) = 70 x 2 + 1
\(x\) + 140 = (140 + 1) x \(x\)
\(x\) + 140 = 141 x \(x\)
\(141\) x \(x\) - \(x\) = 140
\(x\) x (141 - 1) = 140
\(x\) x 140 =140
\(x\) = 140 : 140
\(x\) = 1