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\(A=\frac{0,75+0,6-\frac{3}{7}-\frac{3}{13}}{2,75+2,2-\frac{11}{7}-\frac{11}{13}}\)
\(=\frac{\frac{3}{4}+\frac{3}{5}-\frac{3}{7}-\frac{3}{13}}{\frac{11}{4}+\frac{11}{5}-\frac{11}{7}-\frac{11}{13}}\)
\(=\frac{3.\left(\frac{1}{4}+\frac{1}{5}-\frac{1}{7}-\frac{1}{13}\right)}{11.\left(\frac{1}{4}+\frac{1}{5}-\frac{1}{7}-\frac{1}{13}\right)}\)
\(=\frac{3}{11}\)
Ta có:
\(A=\frac{0,75+0,6-\frac{3}{7}-\frac{3}{13}}{2,75+2,2-\frac{11}{7}-\frac{11}{13}}\)
\(A=\frac{\frac{3}{4}+\frac{3}{5}-\frac{3}{7}-\frac{3}{13}}{\frac{11}{4}+\frac{11}{5}-\frac{11}{7}-\frac{11}{13}}\)
\(A=\frac{3\cdot\left(\frac{1}{4}+\frac{1}{5}-\frac{1}{7}-\frac{1}{13}\right)}{11\cdot\left(\frac{1}{4}+\frac{1}{5}-\frac{1}{7}-\frac{1}{13}\right)}\)
\(A=\frac{3}{11}\)
\(B=\left(0,75-0,6+\frac{3}{7}+\frac{3}{13}\right):\left(\frac{11}{7}+\frac{11}{13}+2,75-2,2\right)\)
\(B=\left(\frac{3}{4}-\frac{3}{5}+\frac{3}{7}+\frac{3}{13}\right):\left(\frac{11}{7}+\frac{11}{13}+\frac{11}{4}-\frac{11}{5}\right)\)
\(B=3\cdot\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{13}\right):11\cdot\left(\frac{1}{7}+\frac{1}{13}+\frac{1}{4}-\frac{1}{5}\right)\)
\(B=\frac{3}{11}\)
Hi Hi!
Ta có : B=(1/5-1/5)-(3/7-3/7)+(5/9-5/9)-(2/11-2/11)+(7/13-7/13)-9/16
B=-9/16
a, \(13.|x|-\frac{16}{3}=\frac{23}{3}\)
\(\Rightarrow13.|x|=13\)
\(\Rightarrow|x|=1\)
\(\Rightarrow x=\left(-1;1\right)\)
\(b,19-\left(|x|+1\right)=18\)
\(\Rightarrow|x|+1=1\)
\(\Rightarrow|x|=0\)
\(\Rightarrow x=0\)
\(c,|x|=5-x\)
\(Th1:x>0\)
\(\Rightarrow x=5-x\)
\(\Rightarrow x+x=5\)
\(\Rightarrow2x=5\)
\(\Rightarrow x=\frac{5}{2}\)
\(Th2:x< 0\)
\(\Rightarrow-x=5-x\)
\(\Rightarrow-x+x=5\)VN
\(a,13.|x|-\frac{16}{3}=\frac{23}{3}\)
\(13.|x|=13\)
TH1:\(13.x=13\)
x=13:13
x=1
TH2:\(13.x=-13\)
x=-13:13
x=-1
\(b,19-\left(|x|+1\right)=18\)
\(|x|+1=1\)
TH1:x+1=1
x=1-1
x=0
TH2:x+1=-1
x=-1+1
x=0
(lạ thật )
\(c,|x|=5-x\)
TH1=>x=5-x
=>x-x=5
=>x=5
TH2:-x=5-x
-x+x=5
Làm theo ý tưởng
a, Lời giải
TH1 : 13.x=13
x=13:13
x=1
13.x=-13
x=-13:13
x=-1
mấy câu kia tương tự
Ta có:S=23+43+63+…+203
=>S=23+43+63+…+203+3+3+3+…+3-3-3-3-…-3
=>S=(23+3)+(43+3)+(63+3)+…+(203+3)-(3+3+3+…+3)
=>S=26+46+66+…+206-(3+3+3+…+3)
Từ 26 đến 206 có:
(206-26):20+1=10(số)
=>S=26+46+66+…+206-3.10
=>S=2.(13+23+33+…+103)-30
mà 13+23+33+…+103=3025
=>S=2.3025-30
=>S=6050-30
=>S=6020
Vậy S=6020.
= 11/16 . (107/13 - 23/13 + 7)
= 11/16 . 175/13 = 1925/208