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71 + 65 x 4 = \(\frac{x+140}{x+260}\)
71 + 260 = \(\frac{x+140}{x+260}\)
331 = \(\frac{x+140}{x+260}\)
\(\Rightarrow x+140=331\left(x+260\right)\)
\(\Rightarrow x+140=331x+86060\)
\(\Rightarrow140-86060=331x-x\)
\(\Rightarrow330x=85920\)
\(\Rightarrow x=\frac{2864}{11}\)
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(x+1)+(x+4)+(x+7)+....+(x+28)=155
x+x+x+...+x+(1+4+7+....+28) = 155
10x + 145 = 155
=> 10x = 155 - 145
=> 10x = 10
=> x = 10:10
=> x =1
a) (x + 1 ) + ( x + 4 ) + ( x + 7 ) + ... + ( x + 28 ) = 155
( x + x + x + ... + x ) + ( 1 + 4 + 7 + ... + 28 ) = 155
10x + 145 = 145
10x = 155 - 145
10x = 10
=> x = 10 : 10
=> x = 1
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71 + 52,5 x 4 = \(\dfrac{x+140}{x}\)+ 210
71 + 210 = (x + 140) : x + 210
71 = x : x + 140 : x (cùng bỏ trừ đi 210)
71 = 1 + 140 : x
71 - 1 = 140 : x
70 = 140 : x
140 : 70 = x
2 = x
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bn ns j mik k hỉu lun đó
gửi câu hỏi lại đi nha
nếu ai đồng ý vs ý kiến của mikk
thì ủng hộ mik nha
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\(\dfrac{x+140}{x}.260=71+65.4\) ( ĐK : x khác 0 )
\(\Leftrightarrow\dfrac{x+140}{x}.260=331\)
\(\Leftrightarrow\dfrac{x+140}{x}=\dfrac{331}{260}\)
\(\Rightarrow260\left(x+140\right)=331x\)
\(\Leftrightarrow x\approx512,7\)
xx+140.260=71+65.4 ( ĐK : x khác 0 )
\Leftrightarrow\dfrac{x+140}{x}.260=331⇔xx+140.260=331
\Leftrightarrow\dfrac{x+140}{x}=\dfrac{331}{260}⇔xx+140=260331
\Rightarrow260\left(x+140\right)=331x⇒260(x+140)=331x
\Leftrightarrow x\approx512,7⇔x sấp sỉ = 512,7