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C=1.2+2.3+...+99.100
3C=1.2.3+2.3.3+...+99.100.3
3C=1.2(3-0)+2.3(4-1)+...+99.100(101-98)
C=99.100.101 phần 3
C=333 300
a)đặt A = 1.2 + 3.4 + 4.5 +...+ 99.100
A=1.2+2.3+3.4+4.5+...+99.100
=>3A=1.2.3+2.3.3+3.4.3+4.5.3+...+99.100.3
=1.2.3+2.3.(4-1)+3.4.(5-2)+4.5.(6-3)+...+99.100.(101-98)
=1.2.3+2.3.4-1.2.3+3.4.5-2.3.4+4.5.6-3.4.5+...+99.100.101-98.99.100
=1.2.3-1.2.3+2.3.4-2.3.4+3.4.5-3.4.5+4.5.6-4.5.6+...+99.100.101
=99.100.101=999900
=>A=999900:3=333300
Vậy A=333300
b)D=2 +4 +6 +333 300
D=4+16+36+333 300
D=20+36+333 300
D=56+333 300
D=333 356
a,xét mẫu số 330,6-72:(a-6) Nếu a=6 thì biểu thức này sẽ không xác định hay A không xác định
b,\(\frac{39,48.17+83.39,48}{330,6-72:\left(a-6\right)}=\frac{39480}{3216}\)
\(\Rightarrow\frac{39,48.\left(83+17\right)}{330,6-72:\left(a-6\right)}=\frac{1645}{134}\)
\(\frac{3948}{330,6-72:\left(a-6\right)}=\frac{1645}{134}\)
\(3948.134=1645.\left[330,6-72:\left(a-6\right)\right]\)
\(\Rightarrow330,6-72:\left(a-6\right)=321,6\)
\(72:\left(a-6\right)=9\)
\(a-6=8\)
\(a=14\)
c,Nhỏ nhất khi 330,6-72:(a-6)=1
72:(a-6)=329,6
a-6=45/206
a=1281/206
Khi \(x=2\), ta có:
\(\left(12-17\right).2\)
\(=\left(-5\right).2\)
\(=-10\)
Khi \(x=4\), ta có:
\(\left(12-17\right).4\)
\(=\left(-5\right).4\)
\(=-20\)
Khi \(x=6\), ta có:
\(\left(12-17\right).6\)
\(=\left(-5\right).6\)
\(=-30\)
\(A=\frac{2^{12}.27^3}{6^7.16^2}=\frac{2^{12}.\left(3^3\right)^3}{2^7.3^7.\left(2^4\right)^2}=\frac{2^{12}.3^9}{2^7.3^7.2^8}=\frac{2^{12}.3^9}{2^{15}.3^7}=\frac{1.3^2}{2^3.1}=\frac{9}{8}\)
\(A=\frac{2^{12}\cdot27^3}{6^7\cdot16^2}\)
\(A=\frac{4096\cdot19683}{279936\cdot256}\)
\(A=\frac{80621568}{71663616}\)
A=\(\frac{72^3.54^2}{108^4}=\frac{\left(2^3.3^2\right)^3.\left(2.3^3\right)^2}{\left(2^2.3^3\right)^4}=\frac{2^9.3^6.2^2.3^6}{2^8.3^{12}}=\frac{2^{11}.3^{12}}{2^8.3^{12}}=2^3=8\)
B= \(\frac{4^6.3^4.9^5}{6^{12}}=\frac{2^{12}.3^4.3^{10}}{2^{12}.3^{12}}=\frac{2^{12}.3^{14}}{2^{12}.3^{12}}=3^2=9\)
c) \(\frac{2^{13}+2^5}{2^{10}+2^2}=\frac{2^5\left(2^8+1\right)}{2^2\left(2^8+1\right)}=2^3=8\)
1.
\(\frac{72^3\times54^2}{108^4}=\frac{\left(8\times9\right)^3\times\left(27\times2\right)^2}{\left(27\times4\right)^4}=\frac{\left(2^3\times3^2\right)^3\times\left(3^3\times2\right)^2}{\left(3^3\times2^2\right)^4}=\frac{\left(2^3\right)^3\times\left(3^2\right)^3\times\left(3^3\right)^2\times2^2}{\left(3^3\right)^4\times\left(2^2\right)^4}=\frac{2^9\times3^6\times3^6\times2^2}{3^{12}\times2^8}=2^3=8\)
2.
\(\frac{4^6\times3^4\times9^5}{6^{12}}=\frac{\left(2^2\right)^6\times3^4\times\left(3^2\right)^5}{\left(2\times3\right)^{12}}=\frac{2^{12}\times3^4\times3^{10}}{2^{12}\times3^{12}}=3^2=9\)
3.
\(\frac{2^{13}+2^5}{2^{10}+2^2}=\frac{2^5\times\left(2^8+1\right)}{2^2\times\left(2^8+1\right)}=2^3=8\)
\(C=2.\left(\frac{3}{1.4}+\frac{3}{4.7}+...+\frac{3}{97.100}\right)\)
\(=2.\left(\frac{1}{1}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+...+\frac{1}{97}-\frac{1}{100}\right)\)
\(=2.\left(1-\frac{1}{100}\right)\)
\(=2.\frac{99}{100}=\frac{198}{100}\)
C = \(3\left(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+....+\frac{3}{97.100}\right)\)
C = \(3\left(\frac{1}{1}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+...+\frac{1}{97}-\frac{1}{100}\right)\)
C = 3 \(\left(1-\frac{1}{100}\right)\)
C = 3 \(\left(\frac{100}{100}-\frac{1}{100}\right)\)
C = \(3.\frac{99}{100}\)
C = \(\frac{297}{100}\)
|-6|-|-2| = 6 – 2 = 4