Tìm x trong tỉ lệ thức:
\(\frac{x-1}{x+5}=\frac{6}{7}\)
tìm x trong tỉ lệ thức sau
\(\frac{x-1}{x+5}=\frac{5}{7}\)
7.(x-1)= 5.(x+5)
7.x-7. = 5.x+25
7.x -5.x =25+7
2.x. = 32
x = 32:2
x. = 16
làm rõ ràng, đầy đủ chi tiết luôn
$\frac{x-1}{x+5}=\frac{5}{7}$
=>(x-1).7=(x+5).5
=>7x-7=5x+25
=>2x=32
=>x=16
Tìm X trong tỉ lệ thức sau :
\(\frac{x-1}{x+7}=\frac{5}{7}\)
lộn na !!
7x - 7 - 5x - 35 = 0
2x + 28 = 0
2x = -28
x = -14
Tìm x trong các tỉ lệ thức sau
a,\(\frac{x-1}{x+5}=\frac{6}{7}\)( \(x\ne-5\))
b, \(\frac{^{x^2}}{6}=\frac{24}{25}\)
c, \(\frac{x-2}{x-4}=\frac{x+4}{x+7}\)
a) \(\frac{x-1}{x+5}=\frac{6}{7}\)
7( x - 1 ) = 6( x + 5 )
7x - 7 = 6x - 30
7x - 6x = -30 + 7
x = -23
b) \(\frac{x^2}{6}=\frac{24}{25}\)
\(x^2.25=6.24\)
\(x^2.25=144\)
\(x^2=\frac{144}{25}\)
\(x=\sqrt{\frac{144}{25}}\)
\(x=\frac{12}{5}\)
c) \(\frac{x-2}{x-4}=\frac{x+4}{x+7}\)
\(\left(x-2\right)\left(x+7\right)=\left(x+4\right)\left(x-4\right)\)
\(x^2+7x-2x-14=x^2-4x+4x-16\)
\(x^2+5x-14=x^2^{ }-16\)
\(x^2-x^2+5x=-16+14\)
\(5x=-2\)\(x=\frac{-2}{5}\)
Tìm x trong các tỉ lệ thức sau
a) x-6 /x+4= 2/7
b) ( x+5) : \(2\frac{1}{2}\)= 40:(x+5)
a, \(\frac{x-6}{x+4}=\frac{2}{7}\Rightarrow7x-42=2x+8\)ĐK : \(x\ne-4\)
\(\Leftrightarrow5x=50\Leftrightarrow x=10\)(tm)
b, \(\left(x+5\right):2\frac{1}{2}=\frac{40}{x+5}\)ĐK : \(x\ne-5\)
\(\Leftrightarrow\frac{5\left(x+5\right)}{2}=\frac{40}{x+5}\Rightarrow5\left(x+5\right)^2=80\Leftrightarrow\left(x+5\right)^2=16\)
TH1 : \(x+5=4\Leftrightarrow x=-1\)
TH2 : \(x+5=-4\Leftrightarrow x=-9\)
tìm x trong các tỉ lệ thức
\(\frac{x-1}{x+5}\)=\(\frac{6}{7}\) ; \(\frac{x^2}{6}\)= \(\frac{24}{25}\) ; \(\frac{x-2}{x-1}\) = \(\frac{x+4}{x+7}\)
a) \(\frac{x-1}{x+5}=\frac{6}{7}\)
\(\Rightarrow7.\left(x-1\right)=6.\left(x+5\right)\)
\(\Rightarrow7x-7=6x+30\)
\(\Rightarrow7x-6x=7+30\)
\(\Rightarrow x=37\)
b) \(\frac{x^2}{6}=\frac{24}{25}\)
\(\Rightarrow25.x^2=24.6\)
\(\Rightarrow25.x^2=144\)
\(\Rightarrow x^2=144:25\)
\(\Rightarrow x^2=\frac{144}{25}\)
\(\Rightarrow x^2=\frac{12^2}{5^2}\)
\(\Rightarrow x^2=\frac{12}{5}^2\)
\(\Rightarrow x=\pm\frac{12}{5}\)
\(c,\frac{x-2}{x-1}=\frac{x+4}{x+7}\)
\(\Leftrightarrow(x-2)(x+7)=(x+4)(x-1)\)
\(\Leftrightarrow x^2+5x-14=x^2+3x-4\)
\(\Leftrightarrow x^2+5x-14-x^2+3x=-4\)
\(\Leftrightarrow\left[x^2-x^2\right]+5x-3x-14=-4\)
\(\Leftrightarrow2x-14=-4\)
\(\Leftrightarrow2x=10\Leftrightarrow x=5\)
Tìm số hữu tỉ x trong tỉ lệ thức :
a) \(0.2:1\frac{1}{5}=\frac{2}{3}:\left(6.x+7\right)\) b) \(\frac{37-x}{x+13}=\frac{3}{7}\)
Giúp mik với ~!!!!!!!!~
Bài 1
Tìm x trong tỉ lệ thức \(\frac{x-3}{5-x}\)= \(\frac{5}{7}\)
\(\frac{x-3}{5-x}=\frac{5}{7}\)
\(\Leftrightarrow\left(x-3\right).7=5.\left(5-x\right)\)
\(\Leftrightarrow7x-21=25-5x\)
\(\Leftrightarrow7x+5x=25+21\)
\(\Leftrightarrow12x=46\)
\(\Leftrightarrow x=\frac{46}{12}=\frac{23}{6}\)
Vậy x = \(\frac{23}{6}\)
tìm x trong tỉ lệ thức : \(\frac{x-2}{x-1}=\frac{x+4}{x+7}\)
\(\Leftrightarrow\left(x-2\right)\left(x+7\right)=\left(x-1\right)\left(x+4\right)\Leftrightarrow x^2+5x-14=x^2+3x-4\Leftrightarrow2x=10\Leftrightarrow x=5\)
\(\frac{x-2}{x-1}=\frac{x+4}{x+7}\)
\(\Leftrightarrow\left(x-2\right)\left(x+7\right)=\left(x-1\right)\left(x+4\right)\)
\(\Leftrightarrow x^2+5x-14=x^2+3x-4\)
\(\Leftrightarrow x^2+15=x^2+3x-4+14\)
\(\Leftrightarrow x^2+15=x^2+3x+10\)
\(\Leftrightarrow x^2+5x-\left(x^2+3x\right)=x^2+3x+10-\left(x^2+3x\right)\)
\(\Leftrightarrow2x=10\)
=> x = 5
Tìm x trong các tỉ lệ thức sau:
a) (3x-2) : \(1\frac{2}{5}=2\frac{3}{7}:2\frac{3}{5}\)
b) x : 0,16 = 9:x
a) \(\frac{3x-2}{1\frac{2}{5}}=\frac{2\frac{3}{7}}{2\frac{3}{5}}\Rightarrow3x-2=1.\frac{2}{5}.\frac{2\frac{3}{7}}{2\frac{3}{5}}=\frac{7}{5}.\frac{17}{7}.\frac{5}{13}\)
\(3x-2=\frac{17}{13}\Rightarrow3x=2+\frac{17}{13}=\frac{43}{13}\Rightarrow x=\frac{43}{39}.\)
b) \(\frac{x}{0,16}=\frac{9}{x}\Rightarrow x^2=9.0,16=1,44\Rightarrow x=\pm1,2\)