Tìm x:
2x.(x-\(\frac{1}{7}\))=0
tìm x
a) \(\frac{7^{x+2}+7^{x+1}7^x}{57}=\frac{5^{2x}5^{2x+1}5^{2x+3}}{131}\)
b) \(\left(2x+3\right)^2+\left(3x-2\right)^4=0\)
Tìm x:
a)7.(x-1)+2x.(1-x)=0
b)0,25-|3,5-x|=0
c)|x+\(\frac{3}{4}\)| -\(\frac{1}{2}\)=0
a, \(7\left(x-1\right)+2x\left(1-x\right)=0\)
\(\Rightarrow\left(7-2x\right)\left(x-1\right)=0\)
\(\Rightarrow\orbr{\begin{cases}7-2x=0\\x-1=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{7}{2}\\x=1\end{cases}}\)
b, \(0,25-\left|3,5-x\right|=0\)
\(\Rightarrow\left|3,5-x\right|=2,5\)
\(\Rightarrow\orbr{\begin{cases}3,5-x=2,5\\3,5-x=-2,5\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=1\\x=6\end{cases}}\)
c, \(\left|x+\frac{3}{4}\right|-\frac{1}{2}=0\)
\(\Rightarrow\left|x+\frac{3}{4}\right|=\frac{1}{2}\)
\(\Rightarrow\orbr{\begin{cases}x+\frac{3}{4}=\frac{1}{2}\\x+\frac{3}{4}=\frac{-1}{2}\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{-1}{4}\\x=\frac{-5}{4}\end{cases}}\)
a) 7.(x-1) + 2x.(1-x) = 0
7.(x-1) - 2x.(x-1) = 0
(x-1).(7-2x) = 0
=> (x-1) = 0 => x = 1
7-2x = 0 => 2x = 7 => x = 7/2
KL:...
b) 0,25 - | 3,5-x| = 0
=> |3,5 - x| = 0,25
TH1: 3,5 - x = 0,25
x = 3,25
TH2: 3,5 - x = -0,25
x = 3,75
phần c bn dựa vào phần b mak lm nha
a) 7.(x - 1) + 2x.(1 - x) = 0
<=> -2x2 + 9x - 7 = 0
<=> \(\orbr{\begin{cases}x=1\\x=\frac{7}{2}\end{cases}}\)
=> \(\orbr{\begin{cases}x=1\\x=\frac{7}{2}\end{cases}}\)
b) 0,25 - |3,5 - x| = 0
<=> - |3,5 - x| = 0 - 0,25
<=> - |3,5 - x| = -0,25
<=> |3,5 - x| = 0,25
Ta xét 2 th:
Th1: |x| = 3,5 - 0,25
<=> |x| = \(\frac{13}{4}\)
Th2: |x| = 3,5 + 0,25
<=> x = \(\frac{15}{4}\)
=> \(\orbr{\begin{cases}x=\frac{13}{4}\\\frac{15}{4}\end{cases}}\)
c) \(\left|x+\frac{3}{4}\right|-\frac{1}{2}=0\)
<=> \(\left|x+\frac{3}{4}\right|=0+\frac{1}{2}\)
<=> \(\left|x+\frac{3}{4}\right|=\frac{1}{2}\)
Ta xét 2 th:
Th1: \(x+\frac{3}{4}=\frac{1}{2}\)
<=> \(x=\frac{1}{2}-\frac{5}{4}\)
<=> \(x=-\frac{3}{4}\)
Th2: \(x+\frac{3}{4}=\frac{1}{2}\)
<=> \(x=\frac{1}{2}-\frac{3}{4}\)
<=> \(x=-\frac{1}{4}\)
=> \(\orbr{\begin{cases}x=-\frac{3}{4}\\x=-\frac{1}{4}\end{cases}}\)
Bài 1 : Tìm x biết :
a, \(\left|\frac{3}{2}x+\frac{1}{2}\right|=\left|4x-1\right|\)
b, \(\left|\frac{5}{4}x-\frac{7}{2}\right|-\left|\frac{5}{8}x+\frac{3}{5}\right|=0\)
c,\(\left|\frac{7}{5}x+\frac{2}{3}\right|=\left|\frac{4}{3}x-\frac{1}{4}\right|\)
Bài 2 : Tìm x biết :
a, | 2x - 5 | = x +1
b, | 3x - 2 | -1 = x
c, | 3x - 7 | = 2x + 1
d, | 2x-1 | +1 = x
1a) \(\left|\frac{3}{2}x+\frac{1}{2}\right|=\left|4x-1\right|\)
=> \(\orbr{\begin{cases}\frac{3}{2}x+\frac{1}{2}=4x-1\\\frac{3}{2}x+\frac{1}{2}=1-4x\end{cases}}\)
=> \(\orbr{\begin{cases}-\frac{5}{2}x=-\frac{3}{2}\\\frac{11}{2}x=\frac{1}{2}\end{cases}}\)
=> \(\orbr{\begin{cases}x=\frac{5}{3}\\x=\frac{1}{11}\end{cases}}\)
b) \(\left|\frac{5}{4}x-\frac{7}{2}\right|-\left|\frac{5}{8}x+\frac{3}{5}\right|=0\)
=>\(\left|\frac{5}{4}x-\frac{7}{2}\right|=\left|\frac{5}{8}x+\frac{3}{5}\right|\)
=> \(\orbr{\begin{cases}\frac{5}{4}x-\frac{7}{2}=\frac{5}{8}x+\frac{3}{5}\\\frac{5}{4}x-\frac{7}{2}=-\frac{5}{8}x-\frac{3}{5}\end{cases}}\)
=> \(\orbr{\begin{cases}\frac{5}{8}x=\frac{41}{10}\\\frac{15}{8}x=\frac{29}{10}\end{cases}}\)
=> \(\orbr{\begin{cases}x=\frac{164}{25}\\x=\frac{116}{75}\end{cases}}\)
c) TT
a, \(\left|\frac{3}{2}x+\frac{1}{2}\right|=\left|4x-1\right|\)
=> \(\orbr{\begin{cases}\frac{3}{2}x+\frac{1}{2}=4x-1\\-\frac{3}{2}x-\frac{1}{2}=4x-1\end{cases}}\)
=> \(\orbr{\begin{cases}\frac{3}{2}x+\frac{1}{2}-4x=-1\\-\frac{3}{2}x-\frac{1}{2}-4x=-1\end{cases}}\)
=> \(\orbr{\begin{cases}x=\frac{3}{5}\\x=\frac{1}{11}\end{cases}}\)
\(b,\left|\frac{5}{4}x-\frac{7}{2}\right|-\left|\frac{5}{8}x+\frac{3}{5}\right|=0\)
=> \(\left|\frac{5}{4}x-\frac{7}{2}\right|-0=\left|\frac{5}{8}x+\frac{3}{5}\right|\)
=> \(\frac{\left|5x-14\right|}{4}=\frac{\left|25x+24\right|}{40}\)
=> \(\frac{10(\left|5x-14\right|)}{40}=\frac{\left|25x+24\right|}{40}\)
=> \(\left|50x-140\right|=\left|25x+24\right|\)
=> \(\orbr{\begin{cases}50x-140=25x+24\\-50x+140=25x+24\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{164}{25}\\x=\frac{116}{75}\end{cases}}\)
c, \(\left|\frac{7}{5}x+\frac{2}{3}\right|=\left|\frac{4}{3}x-\frac{1}{4}\right|\)
=> \(\orbr{\begin{cases}\frac{7}{5}x+\frac{2}{3}=\frac{4}{3}x-\frac{1}{4}\\-\frac{7}{5}x-\frac{2}{3}=\frac{4}{3}x-\frac{1}{4}\end{cases}}\)
=> \(\orbr{\begin{cases}x=-\frac{55}{4}\\x=-\frac{25}{164}\end{cases}}\)
Bài 2 : a. |2x - 5| = x + 1
TH1 : 2x - 5 = x + 1
=> 2x - 5 - x = 1
=> 2x - x - 5 = 1
=> 2x - x = 6
=> x = 6
TH2 : -2x + 5 = x + 1
=> -2x + 5 - x = 1
=> -2x - x + 5 = 1
=> -3x = -4
=> x = 4/3
Ba bài còn lại tương tự
\(\frac{2x+1}{5}=\frac{3y-z}{7}=\frac{2x+3y-1}{6x}\) và x khác 0
tìm x,y
Tìm các số hữu tỉ x
a) (x-\(\frac{4}{7}\)) :(x+\(\frac{1}{2}\))>0
b)(2x-3) :(x+\(\frac{7}{4}\))<0
Tìm x biết:
2x.(x-\(\frac{1}{7}\))=0
\(\Leftrightarrow\hept{\begin{cases}2x=0\\x-\frac{1}{7}=0\end{cases}}\Leftrightarrow\hept{\begin{cases}x=0:2\\x=0+\frac{1}{7}\end{cases}}\)\(\Leftrightarrow\hept{\begin{cases}x=0\\x=\frac{1}{7}\end{cases}}\)
2x(x-1/7)=0
=> 2x=0 hoặc x-1/7=0
=> x=0 hoặc x=1/7
vậy x=0 hoặc x=1/7
tk mk nha
Tìm x biết:
a) 7.(x-1)+2x.(1-x)=0
b) \(\frac{13+x}{37-x}=\frac{7}{3}\)
a)Giải phương trình:\(\left(\frac{x+1}{x-2}\right)^2+\frac{x+1}{x-4}-3\left(\frac{2x-4}{x-4}\right)^2=0\)0
b)Tìm nghiệm nguyên của phương trình: \(2x^2+3xy-2y^2=7.\)
a/ Đặt \(\hept{\begin{cases}\frac{x+1}{x-2}=a\\\frac{x+1}{x-4}=b\end{cases}}\) thì có
\(a^2+b-\frac{12b^2}{a^2}=0\)
\(\Leftrightarrow\left(a^2-3b\right)\left(a^2+4b\right)=0\)
b/ \(2x^2+3xy-2y^2=7\)
\(\Leftrightarrow\left(2x-y\right)\left(x+2y\right)=7\)
tìm x
\(2x\left(x-\frac{1}{7}\right)=0\)
\(2x\left(x-\frac{1}{7}\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}2x=0\\x-\frac{1}{7}=0\end{array}\right.\Leftrightarrow\left[\begin{array}{nghiempt}x=0\\x=\frac{1}{7}\end{array}\right.\)
Vậy \(x\in\left\{0;\frac{1}{7}\right\}\)
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