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Câu a đề thiếu vế phải rồi bạn
b: \(\Leftrightarrow x\cdot0+1=0\)
=>0x+1=0(vô lý)
/x/3+1/=2/3
(=)x/3+1=2/3 hoặc -2/3
Trường hợp 1: x/3+1=2/3
=) x/3= 2/3-1
=) x/3=-1/3
=)X=-1
1) \(\frac{x+1}{15}+\frac{x+2}{14}=\frac{x+3}{13}+\frac{x+4}{12}\)
\(\Leftrightarrow\frac{x+16}{15}+\frac{x+16}{14}-\frac{x+16}{13}-\frac{x+16}{12}=0\)
\(\Leftrightarrow\left(x+16\right)\left(\frac{1}{15}+\frac{1}{14}-\frac{1}{13}-\frac{1}{12}\right)=0\)
\(\Leftrightarrow x=-16\)
2)3)4) tương tự
Gợi ý : 2) cộng 3 vào cả hai vế
3)4) cộng 2 vào cả hai vế
5) \(\frac{x+1}{20}+\frac{x+2}{19}+\frac{x+3}{18}=-3\)
\(\Leftrightarrow\frac{x+21}{20}+\frac{x+21}{19}+\frac{x+21}{18}=0\)
\(\Leftrightarrow\left(x+21\right)\left(\frac{1}{20}+\frac{1}{19}+\frac{1}{18}\right)=0\)
\(\Leftrightarrow x=-21\)
6) sửa VT = 4 rồi tương tự câu 5)
Bài 1c)
\(\frac{1}{3}+x=\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+...+\frac{1}{110}\)
\(\frac{1}{3}+x=\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+...+\frac{1}{10.11}\)
\(\frac{1}{3}+x=\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{10}-\frac{1}{11}\)
\(\frac{1}{3}+x=\frac{1}{3}-\frac{1}{11}=\frac{11}{33}-\frac{3}{33}=\frac{8}{33}\)
\(x=\frac{8}{33}-\frac{1}{3}=\frac{8}{33}-\frac{11}{33}=\frac{-3}{33}=\frac{-1}{11}\)
a) \(x:\left(-\frac{1}{3}\right)^3=-\frac{1}{3}\)
\(\Rightarrow x=\left(-\frac{1}{3}\right).\left(-\frac{1}{3}\right)^3\)
\(\Rightarrow x=\left(-\frac{1}{3}\right)^4\)
\(\Rightarrow x=\frac{1}{81}\)
Vậy \(x=\frac{1}{81}.\)
b) \(\frac{3}{4}:\frac{41}{99}=x:\frac{75}{90}\)
\(\Rightarrow\frac{297}{164}=x:\frac{75}{90}\)
\(\Rightarrow x=\frac{297}{164}.\frac{75}{90}\)
\(\Rightarrow x=\frac{495}{328}\)
Vậy \(x=\frac{495}{328}.\)
c) \(x+\left|-\frac{1}{2}\right|=3\frac{1}{3}-4\frac{1}{2}\)
\(\Rightarrow x+\frac{1}{2}=\frac{10}{3}-\frac{9}{2}\)
\(\Rightarrow x+\frac{1}{2}=-\frac{7}{6}\)
\(\Rightarrow x=\left(-\frac{7}{6}\right)-\frac{1}{2}\)
\(\Rightarrow x=-\frac{5}{3}\)
Vậy \(x=-\frac{5}{3}.\)
Chúc bạn học tốt!
a)\(\frac{1}{4}-\frac{1}{3}x=\frac{2}{5}-\frac{3}{2}x\)
\(\Leftrightarrow\)\(\frac{15-20x}{60}=\frac{24-90x}{60}\)
\(\Leftrightarrow15-20x=24-90x\)
\(\Leftrightarrow-20x+90x=24-15\)
\(\Leftrightarrow70x=9\)
\(\Leftrightarrow x=\frac{9}{70}\)
c) (1/2-1/6)*3^x+4-4*3^x=3^16-4*3^13
=1/3*3^x*3^4-4*3^x=3^13*3^3-4*3^13
=27*3^x-4*3^x=3^13*(27-4)
=3^x*(27-4)=3^13*(27-4)
=>x=13
a, 2/1/3:1/3=7/9:x b, x:1/3=12/99:15/90
7 = 7/9 : x x :1/3= 8/11
x = 7/9:7 x = 8/11 * 1/3
x = 1/9 x = 8/33
c, 0,15:x=3/1/3:2,25 d, 3/4:0,75=x:75/90
0,15:x =40/27 1 =x:75/90
x = 0,15:40/27 x = 1*75/90
x = 81/800 x = 75/90
e, x/-15=-60/x f, -2/x=-x/8
=>x*x=-15*(-60) => (-2)*8=x*-x
=>x2=900 => -16 = -x2
=>x2=302 hoặc x2=(-30)2 => 16=x2
=> x=30 hoặc x= -30 => x2=42 hoặc x2=(-4)2
=> x=4 hoặc x=-4
a)\(2\frac{1}{3}:\frac{1}{3}=\frac{7}{9}:x\)
\(\frac{7}{3}\times3=\frac{7}{9}:x\)
\(7=\frac{7}{9}:x\)
\(x=\frac{7}{9}:7\)
\(x=\frac{7}{9}\times\frac{1}{7}\)
\(x=\frac{1}{9}\)