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= \(10^2+8^2+6^2+4^2+2^2-9^2-7^2-5^2-3^2-1\)-1
=\(55\)
\(\left(10^2+8^2+6^2+4^2+2^2\right)-\left(9^2+7^2+5^2+3^2+1^2\right)\)
\(=10^2+8^2+6^2+4^2+2^2-9^2-7^2-5^2-3^2-1^2\)
\(=\left(10^2-9^2\right)+\left(8^2-7^2\right)+...+\left(2^2-1^2\right)\)
\(=\left(10-9\right)\left(10+9\right)+\left(8-7\right)\left(8+7\right)+...+\left(2-1\right)\left(1+2\right)\)
\(=10+9+8+7+...+2+1\)
\(=\frac{\left(1+10\right)\cdot10}{2}\)
\(=55\)
Bài làm:
Ta có: \(\left(10^2+8^2+...+2^2+1^2\right)-\left(9^2+7^2+...+1^2\right)\)
\(=\left(10^2-9^2\right)+\left(8^2-7^2\right)+...+\left(2^2-1^2\right)+1\)
\(=\left(10-9\right)\left(10+9\right)+\left(8-7\right)\left(8+7\right)+...+\left(2-1\right)\left(2+1\right)+1\)
\(=19.1+15.1+...+3.1+1\)
\(=1+3+7+11+15+19\)
\(=56\)
\(\left(1+1+1\right)!=6\)
\(2+2+2=6\)
\(\left(3+3-3\right)!=6\)
\(\sqrt{4}+\sqrt{4}+\sqrt{4}=6\)
\(5+5:5=6\)
\(7-7:7=6\)
\(\sqrt{8+\left(8:8\right)}!=6\)
\(\left(9-9\right)+\sqrt{9}!=6\)
\(\sqrt{10-\left(10:10\right)}!=6\)
Tất cả các phép đều sai
~~ tk mk nhé....~~
Ai tk mk mk tk lại ~~~
Kb lun nha....n_n
Giải:
\(\left(10^2+8^2+6^2+4^2+2^2\right)-\left(1^2+3^2+5^2+7^2+9^2\right)\)
\(=10^2+8^2+6^2+4^2+2^2-1^2-3^2-5^2-7^2-9^2\)
\(=10^2-9^2+8^2-7^2+6^2-5^2+4^2-3^2+2^2-1^2\)
\(=\left(10^2-9^2\right)+\left(8^2-7^2\right)+\left(6^2-5^2\right)+\left(4^2-3^2\right)+\left(2^2-1^2\right)\)
\(=\left(10-9\right)\left(10+9\right)+\left(8-7\right)\left(8+7\right)+\left(6-5\right)\left(6+5\right)+\left(4-3\right)\left(4+3\right)+\left(2-1\right)\left(2+1\right)\)
\(=\left(10+9\right)+\left(8+7\right)+\left(6+5\right)+\left(4+3\right)+\left(2+1\right)\)
\(=10+9+8+7+6+5+4+3+2+1\)
\(=55\)
Vậy ...
\(C=10^2+8^2+6^2...+2^2-\left(9^2+7^2+5^2+...+1^2\right)\)
\(\Rightarrow C=\left(10^2-9^2\right)+\left(8^2-7^2\right)+...+\left(2^2-1^2\right)\)
\(\Rightarrow C=\left(10-9\right)\left(10+9\right)+\left(8-7\right)\left(8+7\right)+...+\left(2-1\right)\left(2+1\right)\)
\(\Rightarrow C=19+15+...+3\)
Vậy C = {(19 + 3)[(19-3):4+1]} :2 = 60
\(C=10^2-9^2+8^2-...-3^2+2^2-1^2\)
\(=\left(10+9\right)\left(10-9\right)+\left(8+7\right)\left(8-7\right)+...+\left(2+1\right)\left(2-1\right)\)
\(=10+9+8+...+2+1\)
\(=\frac{\left(1+10\right)10}{2}=55\)
Vậy C=55