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(x-1/2).5/3=7/4-1/2
(x-1/2).5/3=5/4
x-1/2=5/4:5/3
x=3/4+1/2
x=5/4
(x-4/3).7/4=5-7/6
(x+4/3).7/4=23/6
x+4/3=23/6:7/4
x+4/3=46/21
x=46/21-4/3
x=6/7
tốt nhất để tớ chả lời cho
a,4/7.x=1/5+2/3
4/7.x=13/15
13/15:4/7=91/60
b
=-7/8.x=1/3-2/9
-7/8.x=1/9
x=1/9:7/8
x=8/63
c
5/7:x=1/6-4/5
5/7:x=-19/30
x=-116/133
a) (x+1) ^2 = 25
(x+1) ^2 = 5^2
x + 1 = 5 Hoặc x + 1 = -5
x = 5 - 1 x = -5 - 1
x = 4 x = -6
b) 4^5.4^x-1 = 4^7
4^x-1 = 4^7:4^5
4^x-1 = 4^7-5
4^x-1 = 4^2
x- 1 = 2
x = 2+1
x = 3
\(a,x+\frac{3}{4}=\frac{1}{4}\)
\(\Rightarrow x=\frac{1}{4}-\frac{3}{4}=-\frac{1}{2}\)
\(b,\frac{2}{3}x-\frac{3}{7}=\frac{1}{7}\)
\(\Rightarrow\frac{2}{3}x=\frac{1}{7}+\frac{3}{7}\)
\(\Rightarrow\frac{2}{3}x=\frac{4}{7}\)
\(\Rightarrow x=\frac{4}{7}:\frac{2}{3}=\frac{4}{7}\cdot\frac{3}{2}=\frac{6}{7}\)
\(c,1\frac{2}{3}x-50\%x=-1\frac{1}{6}\)
\(\Rightarrow\frac{5}{3}x-\frac{50}{100}x=-\frac{7}{6}\)
\(\Rightarrow\left[\frac{5}{3}-\frac{50}{100}\right]x=-\frac{7}{6}\)
\(\Rightarrow\left[\frac{5}{3}-\frac{1}{2}\right]x=-\frac{7}{6}\)
\(\Rightarrow\frac{7}{6}x=-\frac{7}{6}\Leftrightarrow x=-\frac{7}{6}:\frac{7}{6}=-\frac{7}{6}\cdot\frac{6}{7}=-1\)
a,x+\(\frac{3}{4}\)=\(\frac{1}{4}\)
=>x =\(\frac{1}{4}\)-\(\frac{3}{4}\)
=> x =\(\frac{-1}{2}\)
Vậy x=\(\frac{-1}{2}\)
b,\(\frac{2}{3}\)x-\(\frac{3}{7}\)=\(\frac{1}{7}\)
=>\(\frac{2}{3}\)x =\(\frac{1}{7}\)+\(\frac{3}{7}\)
=>\(\frac{2}{3}\)x =\(\frac{4}{7}\)
=> x =\(\frac{4}{7}\) :\(\frac{2}{3}\)
=> x =\(\frac{4}{7}\).\(\frac{3}{2}\)
=> x =\(\frac{6}{7}\)
Vậy x=\(\frac{6}{7}\)
c,\(\frac{12}{3}\)x-50%x =\(\frac{-11}{6}\)
=>\(\frac{12}{3}\)x-\(\frac{1}{2}\)x=\(\frac{-11}{6}\)
=>x(\(\frac{12}{3}\)-\(\frac{1}{2}\))=\(\frac{-11}{6}\)
=>x(\(\frac{24}{6}\)-\(\frac{3}{6}\))=\(\frac{-11}{6}\)
=>x\(\frac{21}{6}\) =\(\frac{-11}{6}\)
=>x =\(\frac{-11}{6}\):\(\frac{21}{6}\)
=>x =\(\frac{-11}{6}\).\(\frac{6}{21}\)
=>x =\(\frac{-11}{21}\)
Vậy x=\(\frac{-11}{21}\)
a)\(\Rightarrow\)/x-7/=19
\(\Rightarrow\)x-7\(\in\)19;-19
sau đó bạn thử từng trường hợp
Vậy x\(\in\)26;-12
b)\(\Rightarrow\)\(\left(x-\frac{1}{2}\right)\div\frac{1}{3}+\frac{5}{7}=\frac{68}{7}\)
\(\Rightarrow\left(x-\frac{1}{2}\right)\div\frac{1}{3}=\frac{63}{7}=9\)
\(\Rightarrow x-\frac{1}{2}=9\times\frac{1}{3}=3\)
\(\Rightarrow x=3+\frac{1}{2}=\frac{7}{2}\)
1a) \(\frac{x-3}{x+7}=\frac{-5}{-6}\)
=> \(\frac{x-3}{x+7}=\frac{5}{6}\)
=> (x - 3).6 = 5.(x + 7)
=> 6x - 18 = 5x + 35
=> 6x - 5x = 35 + 18
=> x = 53
b) \(\frac{x-7}{x+3}=\frac{4}{3}\)
=> (x - 7). 3 = (x + 3). 4
=> 3x - 21 = 4x + 12
=> 3x - 4x = 12 + 21
=> -x = 33
=> x = -33
c) \(\frac{x-10}{6}=-\frac{5}{18}\)
=> (x - 10) . 18 = -5 . 6
=> 18x - 180 = -30
=> 18x = -30 + 180
=> 18x = 150
=> x = 150 : 18 = 25/3
d) \(\frac{x-2}{4}=\frac{25}{x-2}\)
=> (x - 2)(x - 2) = 25 . 4
=> (x - 2)2 = 100
=> (x - 2)2 = 102
=> \(\orbr{\begin{cases}x-2=10\\x-2=-10\end{cases}}\)
=> \(\orbr{\begin{cases}x=12\\x=-8\end{cases}}\)
e) \(\frac{7}{x}=\frac{x}{28}\)
=> 7 . 28 = x . x
=> 196 = x2
=> x2 = 142
=> \(\orbr{\begin{cases}x=14\\x=-14\end{cases}}\)
f) \(\frac{40+x}{77-x}=\frac{6}{7}\)
=> (40 + x) . 7 = (77 - x).6
=> 280 + 7x = 462 - 6x
=> 280 - 462 = -6x + 7x
=> -182 = x
=> x = -182
a) 150 : [17 - (2x - 3)] = 350
=> 17 - (2x - 3) = \(\frac{150}{350}=\frac{3}{7}\)
=> 2x - 3 = \(17-\frac{3}{7}=\frac{116}{7}\)
=> 2x = \(\frac{116}{7}+3\)
=> 2x = \(\frac{137}{7}\)
=> x = \(\frac{137}{7}:2=\frac{137}{14}\)
b) 4 . [105 - (x - 9)] - 486 = 0
=> 4. [105 - (x - 9)] = 486
=> 105 - (x - 9) = 243/2
=> x - 9 = \(105-\frac{243}{2}=-\frac{33}{2}\)
=> x = \(-\frac{33}{2}+9=-\frac{15}{2}\)
c) 1000 - 2{600 - 4.[198 - 7.(21 - 7)]}.x = 200
=> 1000 - 2{600 - 4.[198 - 7.14]}.x = 200
=> 1000 - 2{600 - 4.[198 - 98].x = 200
=> 1000 - 2{600 - 4.100}.x = 200
=> 1000 - 2{600 -400}.x = 200
=> 1000 - 2.200.x = 200
=> 2.200.x = 800
=> 400.x = 800
=> x = 2
Câu 2 :
a) 350 : [19 - (7x - 3)] = 350
=> 19 - (7x - 3) = 1
=> 7x - 3 = 18
=> 7x = 21
=> x = 3
b) 7.[109 - (x - 9)] - 420 = 0
=> 7.[109 - (x - 9)] = 420
=> 109 - (x - 9) = 60
=> x - 9 = 49
=> x = 49 + 9 = 58
c) 254 - 2{200 - 4.[90 - 7.(19 - 9)]}.x = 54
=> 254 - 2{200 - 4.[90 - 7.10]}.x = 54
=> 254 - 2{200 - 4[90 - 70]} . x= 54
=> 254 - 2{200 - 4.20} . x = 54
=> 254 - 2{200 - 80}.x = 54
=> 254 - 2.120 . x= 54
=> 2.120.x = 200
=> 240.x = 200
=> \(x=\frac{5}{6}\)
