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a) | x - 1,5 | = 2
=>x - 1,5 =2 hoặc x - 1,5 = -2
Th1:
x - 1,5 =2
x=2+1,5
x=3,5
Th2:
x - 1,5 = -2
x=-2+1,5
x=-0,5
Vậy x\(\in\){3,5:-0,5}
\(\frac{1}{2}x+\frac{1}{5}x+\frac{3}{5}=0\)
=> \(\left(\frac{1}{2}+\frac{1}{5}\right)x+\frac{3}{5}=0\)
=> \(\frac{7}{10}x+\frac{3}{5}=0\)
=> \(\frac{7}{10}x=-\frac{3}{5}\)
=> \(x=\left(-\frac{3}{5}\right):\frac{7}{10}=\left(-\frac{3}{5}\right)\cdot\frac{10}{7}=\left(-\frac{3}{1}\right)\cdot\frac{2}{7}=-\frac{6}{7}\)
b) \(\left|2\frac{1}{2}+x\right|-\left(-\frac{2}{3}\right)=3\)
=> \(\left|\frac{5}{2}+x\right|+\frac{2}{3}=3\)
=> \(\left|\frac{5}{2}+x\right|=\frac{7}{3}\)
=> \(\orbr{\begin{cases}\frac{5}{2}+x=\frac{7}{3}\\\frac{5}{2}+x=-\frac{7}{3}\end{cases}}\Rightarrow\orbr{\begin{cases}x=-\frac{1}{6}\\x=-\frac{29}{6}\end{cases}}\)
c) \(\left|x+\frac{4}{15}\right|-\left|-3.75\right|=-\left|-2,15\right|\)
=> \(\left|x+\frac{4}{15}\right|-3,75=-2,15\)
=> \(\left|x+\frac{4}{15}\right|=\frac{8}{5}\)
=> \(\orbr{\begin{cases}x+\frac{4}{15}=\frac{8}{5}\\x+\frac{4}{15}=-\frac{8}{5}\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{4}{3}\\x=-\frac{28}{15}\end{cases}}\)
a, \(\frac{1}{2}x+\frac{1}{5}x+\frac{3}{5}=0\Leftrightarrow\frac{7}{10}x+\frac{3}{5}=0\Leftrightarrow x=-\frac{6}{7}\)
b, đề sai
c, \(\left|\frac{x+4}{15}\right|-\left|-3,75\right|=-\left|-2,15\right|\)
\(\Leftrightarrow\frac{x+4}{15}-3,75=-2,15\Leftrightarrow\frac{x+4}{15}=\frac{8}{5}\Leftrightarrow x+4=24\Leftrightarrow x=28\)
a) 420 + 65 . 4 = ( x + 175 ) : 5 + 30
680 = ( x + 175 ) : 5 + 30
( x + 175 ) : 5 = 680 - 30
( x + 175 ) : 5 = 650
x + 175 = 650 . 5
x + 175 = 3250
x = 3250 - 175
x = 3075
Những câu sau làm giống vậy
a.420 + 65 . 4 = ( x + 175 ) : 5 + 30
680 = ( x + 175 ) : 5 + 30
( x + 175 ) : 5 = 680 - 30
( x + 175 ) : 5 = 650
x + 175 = 650 x 5
x + 175 = 3250
x = 3250 - 175
x = 3075
[ ( x + 32 ) - 17 ] . 2 = 42
[ ( x + 32 ) - 17 ] = 42 : 2
( x + 32 ) - 17 = 21
( x + 32 ) = 21 + 17
x + 32 = 38
x = 38 - 32
x = 6
b. ( 32 . 15 ) : 2 = ( x + 70) : 14 - 40
240 = ( x + 70 ) : 14 - 40
( x + 70 ) : 14 = 240 + 40
( x + 70 ) : 14 = 280
( x + 70 ) = 280 . 14
x + 70 = 3820
x = 3920 - 70
x = 3850
a)
\(\frac{-2}{-15}-x=\frac{-3}{10}\)
\(x=\frac{4}{30}+\frac{9}{30}\)
\(x=\frac{13}{30}\)
b)
\(x-\frac{1}{15}=\frac{1}{10}\)
\(x=\frac{3}{30}+\frac{2}{30}\)
\(x=\frac{5}{30}=\frac{1}{6}\)
c)
\(\frac{-3}{8}-x=\frac{5}{12}\)
\(x=\frac{-9}{24}-\frac{10}{24}\)
\(x=\frac{-19}{24}\)
\(\left|x+\frac{4}{15}\right|-\left|-3,75\right|=-\left|-2,15\right|\)
=> \(\left|x+\frac{4}{15}\right|-3,75=-2,15\)
=> \(\left|x+\frac{4}{15}\right|=-2,15+3,75\)
=> \(\left|x+\frac{4}{15}\right|=1,6=\frac{8}{5}\)
=> \(\orbr{\begin{cases}x+\frac{4}{15}=\frac{8}{5}\\x+\frac{4}{15}=\frac{-8}{5}\end{cases}}\)=> \(\orbr{\begin{cases}x=\frac{4}{3}\\x=\frac{-28}{15}\end{cases}}\)
| x + 4/15 | - | - 3,75 | = - | - 2,15 |
| x + 4/15 | - 3,75 = - 2,15
| x + 4/15 | = - 2,15 + 3,75
| x + 4/15 | = 1,6
Trường hợp 1 : x + 4/15 = 1,6 suy ra x = 4/3
Trương hợp 2: x + 4/15 = - 1,6 suy ra x = -28/15
\(\left|x+\frac{4}{15}\right|-\left|-3,75\right|=-\left|-2,15\right|\)
\(\Rightarrow\left|x+\frac{4}{15}\right|-3,75=-2,15\)
\(\Rightarrow\left|x+\frac{4}{15}\right|=-2,15+3,75\)
\(\Rightarrow\left|x+\frac{4}{15}\right|=1,6\)
\(\Rightarrow\left|x+\frac{4}{15}\right|=\frac{8}{5}\)
\(\Rightarrow\left[\begin{array}{nghiempt}x+\frac{4}{15}=\frac{8}{5}\\x+\frac{4}{15}=-\frac{8}{5}\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}x=\frac{4}{3}\\x=-\frac{28}{15}\end{array}\right.\)
Ta có : \(\left|x+\frac{4}{15}\right|-\left|-3,75\right|=-\left|-2,15\right|\)
\(\Leftrightarrow\left|x+\frac{4}{15}\right|=3,75-2,15=\frac{8}{5}\)
\(\Rightarrow\left[\begin{array}{nghiempt}x+\frac{4}{15}=\frac{8}{5}\\-x-\frac{4}{15}=\frac{8}{5}\end{array}\right.\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=\frac{4}{3}\\x=-\frac{28}{15}\end{array}\right.\)
a)
| x - 1,5 | = 2
+) x - 1,5 = 2
=> x = 3,5
+) x - 1,5 = -2
=> x = -0,5
b) c) tường tự
haiz
b) | x + 3/4 | - 1/2 = 0
| x + 3/4 | = 1/2
+) x + 3/4 = 1/2
=> x = -1/4
+) x + 3/4 = -1/2
=> x = -5/4
Vậy,.......