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\(a,\)\(71+65\times4=\frac{x+140}{x}+260\)
\(\Rightarrow71+260=\frac{x-140}{x}+260\)
\(\Rightarrow71=\frac{x-140}{x}\)
\(\Rightarrow71x=x-140\)
\(\Rightarrow71x-x=-140\)
\(\Rightarrow70x=-140\)
\(\Rightarrow x=-2\)
\(b,\)\(y\times\frac{15}{2}-\frac{1}{3}\times\left(\frac{1}{4}+y\right)=90\frac{2}{3}\)
\(\Rightarrow\frac{15y}{2}-\frac{1}{12}-\frac{y}{3}=\frac{272}{3}\)
\(\Rightarrow\frac{90y}{12}-\frac{1}{12}-\frac{4y}{12}=\frac{1088}{12}\)
\(\Rightarrow90y-1-4y=1088\)
\(\Rightarrow86y=1089\)
\(\Rightarrow y=\frac{1089}{86}\)
( X x 0,25+ 1999) x2000= ( 53+1999) x2000
( X x 0,25+ 1999) = ( 53+1999)x2000:2000
( X x 0,25+1999) =( 53+1999)
( X x 0,25+1999) = 2052
X+0,25 = 2052 - 1999
X+ 0,25 = 53
X = 53:0,25
X = 212
71+65 x4 = x+140/x + 260
x+140/x + 260= 71+65x4
x+140/x + 260=71 + 260
x+140/x=71
x/x +140/x=71
1+ 140/x=71
140/x=71-1
140/x=70
x=140/70
x=2
k nha linh
( x + 1 ) + ( x + 4 ) + ( x + 7 ) + ( x + 10) + ..........+ ( x + 28 ) = 155
10x + ( 1 + 4 + 7 + ... + 28 ) = 155
10x + 145 = 155
10x = 155 - 145
10x = 10
x = 10 : 10
Vậy x = 1
\(a,\left[x+1\right]+\left[x+4\right]+\left[x+7\right]+\left[x+10\right]+...+\left[x+28\right]=155\)
\(\Leftrightarrow x+1+x+4+x+7+x+10+...+x+28=155\)
\(\Leftrightarrow(x+x+x+...+x)+(1+4+7+...+28)=155\)
\(\Leftrightarrow10x+145=155\)
\(\Leftrightarrow10x=155-145\)
\(\Leftrightarrow10x=10\)
\(\Leftrightarrow x=1\)
\(b)(x\times0,25+1999)\times2000=(53+1999)\times2000\)
\(\Leftrightarrow(x\times0,25+1999)\times2000=4104000\)
\(\Leftrightarrow(x\times0,25+1999)=4104000:2000\)
\(\Leftrightarrow(x\times0,25+1999)=2052\)
\(\Leftrightarrow x\times0,25=2052-1999\)
\(\Leftrightarrow x\times0,25=53\)
\(\Leftrightarrow x=53:0,25=212\)
Câu c tự làm
#)Giải :
\(71+65.4=\frac{x+140}{x}+260\)
\(\frac{x+140}{x}+260=71+65.4\)
\(\frac{x+140}{x}+260=71+260\)
\(\frac{x+140}{x}=71\)
\(\frac{x}{x}+\frac{140}{x}=71\)
\(1+\frac{140}{x}=71\)
\(\frac{140}{x}=71-1\)
\(\frac{140}{x}=70\)
\(x=140:70\)
\(x=2\)
#~Will~be~Pens~#
\(71+65.4=\frac{x+140}{x}+260\)
\(\Rightarrow\frac{x+140}{x}+260=71+65.4\)
\(\frac{x+140}{x}+260=331\)
\(\frac{x+140}{x}=331-260=71\)
\(\frac{x}{x}+\frac{140}{x}=71\)
\(1+\frac{140}{x}=71\)
\(\frac{140}{x}=71-1=70\)
\(x=\frac{140}{70}=2\)
Vậy x=2
Để mình giải lần nữa cho:
71 + 65 x 4 = \(\frac{x+140}{x}+260\)
71 + 260 = \(\frac{x}{x}+\frac{140}{x}+260\)
71 = \(1+\frac{140}{x}\)
\(71-1\) = \(\frac{140}{x}\)
70 = \(\frac{140}{x}\)
x = 140 : 70
x = 2
cho mk 1 cái l-i-k-e đi minh phương cái này mk giải đầu mà