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Đặt thừa số chung x.
Ta có:
\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+9\right)\Leftrightarrow x+\left(1+2+3+...+9\right)=135\)
\(\Leftrightarrow x+\left(1+2+3+4+5+6+7+8+9\right)\Leftrightarrow x+45=135\)
\(\Rightarrow x=135-45=90\)
Đs:
x * 10 + (1 + 2 + 3 ... +9) = 135
x *10 + 45 =135
x * 10 = 135 - 45
x * 10 = 90
x =90 : 10
x = 9
Vậy x = 9
thử lại:(tự làm)
\(x-\left(\frac{5}{6}-x\right)=x-\frac{2}{3}\)
\(\Leftrightarrow x-\frac{5}{6}+x=x-\frac{2}{3}\)
\(\Leftrightarrow\left(x-x\right)+\frac{5}{6}=x-\frac{2}{3}\)
\(\Leftrightarrow0+\frac{5}{6}=x-\frac{2}{3}\)
\(\Leftrightarrow x-\frac{2}{3}=\frac{5}{6}\)
\(\Leftrightarrow x=\frac{5}{6}+\frac{2}{3}\)
\(\Leftrightarrow x=\frac{5}{6}+\frac{4}{6}\)
\(\Leftrightarrow x=\frac{3}{2}\)
Mình trình bày theo cách mình hiểu thông cảm nha
1 kg/dm*3 = 1000 g/cm*3
1g/cm*3 =1/1000 kg/dm*3
ví dụ :
3,2kg/dm*3 =3200g/cm*3
2,7g/cm*3 = 0,0027kg/dm*3
gook luck too you !
\(\frac{1}{2}+\frac{1}{5}+\frac{2}{9}\)
=\(\frac{45}{90}+\frac{18}{90}+\frac{20}{90}\)
=\(\frac{83}{90}\)
\(x+2x+3x+...+100x=2200\)
=>\(x\left(1+2+3+...+100\right)=2200\)
=>\(x.\frac{100.101}{2}=2200\)
=>\(x.5050=2200\)
=>x=2200:5050
=>x=\(\frac{44}{101}\)
\(x+2x+3x+...+100x=220\)
\(\Rightarrow x\left(1+2+3+....+100\right)=2200\)
\(\Rightarrow5050x=2200\)
\(\Rightarrow x=\frac{44}{101}\)
\(\frac{3}{2}+\frac{3}{8}+\frac{3}{32}+\frac{3}{128}+\frac{3}{512}\)
\(=\left(\frac{12}{8}+\frac{3}{8}\right)+\left(\frac{12}{128}+\frac{3}{128}\right)+\frac{3}{512}\)
\(=\frac{15}{8}+\frac{15}{128}+\frac{3}{512}\)
\(=\frac{240}{128}+\frac{15}{128}+\frac{3}{512}\)
\(=\frac{255}{128}+\frac{3}{512}\)
\(=\frac{1020}{512}+\frac{3}{512}\)
\(=\frac{1023}{512}\)
\(\frac{3}{2}+\frac{3}{8}+\frac{3}{32}+\frac{3}{128}+\frac{3}{512}=\frac{3}{1.2}+\frac{3}{2.4}+\frac{3}{4.8}+\frac{3}{8.16}+\frac{3}{16.32}\)
\(=\frac{3}{1}-\frac{3}{2}+\frac{3}{2}-\frac{3}{4}+\frac{3}{8}-\frac{3}{8}+\frac{3}{16}-\frac{3}{16}+\frac{3}{32}\)
\(=3+\frac{3}{32}=\frac{3.32}{32}+\frac{3}{32}=\frac{96+3}{32}=\frac{99}{32}\)
| x - 2 | + 1 = 5
| x - 2 | = 5 + 1
| x - 2 | =
Th1 : => x - 2 = 6
x = 6 + 2
x = 8
Th2 : => x - 2 = -6
x = -6 + 2
x = -4
vậy x = -4 hoặc = 8
bn k ch mk nha