(-7/4)^2+(-3/4)^9.64-2018^0
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![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a: =>x-2017=0 và y-2018=0
=>x=2017; y=2018
b: =>3x-y=0 và y+2/3=0
=>y=-2/3 và 3x=-2/3
=>x=-2/9 và y=-2/3
c: =>3/4x-1/2=0 và 4/5y+6/25=0
=>x=2/3 và y=-3/10
![](https://rs.olm.vn/images/avt/0.png?1311)
[36.4-4.(82-7.10)2:4]-20180
=[144-4.(82-70)2:4]-1
=[144-4.122:4]-1
=[144-576:4]-1
=[144-144]-1
=0-1
=-1
=[36.4-4.(82-70)2:4]-1
=[36.4-4.122:4]-1
=[36.4-4.144:4]-1
=[144-576:4]-1
=[144-144]-1
=0-1
=-1
![](https://rs.olm.vn/images/avt/0.png?1311)
Bài 1:
a, \(A=3^{100}+3^{99}+...+3+1\)
\(\Rightarrow3A=3^{101}+3^{100}+...+3^2+3\)
\(\Rightarrow3A-A=\left(3^{101}+3^{100}+...+3^2+3\right)-\left(3^{100}+3^{99}+...+3+1\right)\)
\(\Rightarrow2A=3^{101}+1\Rightarrow A=\dfrac{3^{101}+1}{2}\)
b, \(B=\dfrac{15^9.2^{18}.9^8}{3^{15}.4^8.25^4}=\dfrac{3^9.5^9.2^{18}.3^{16}}{3^{15}.2^{16}.5^8}\)
\(=3^{10}.5.2^2=472392\)
c, \(C=\dfrac{2^{10}.10^{17}.7^9}{5^{15}.14^9.64^9}=\dfrac{2^{10}.2^{17}.5^{17}.7^9}{5^{15}.2^9.7^9.2^{54}}\)
\(=\dfrac{5^2}{2^{36}}\)
Chúc bạn học tốt!!!
1.
\(A=3^{100}+3^{99}+3^{98}+...+3^2+3+1\\ A=\dfrac{3-1}{2}\cdot\left(3^{100}+3^{99}+3^{98}+...+3^2+3+1\right)\\ =\dfrac{\left(3-1\right)\cdot\left(3^{100}+3^{99}+3^{98}+...+3^2+3+1\right)}{2}\\ =\dfrac{3^{101}-3^{100}+3^{100}-3^{99}+...+3^2-3+3-1}{2}\\ =\dfrac{3^{101}-1}{2}\)
\(B=\dfrac{15^9\cdot2^{18}\cdot9^8}{3^{15}\cdot4^8\cdot25^4}\\ =\dfrac{\left(3\cdot5\right)^9\cdot2^{18}\cdot\left(3^2\right)^8}{3^{15}\cdot\left(2^2\right)^8\cdot\left(5^2\right)^4}\\ =\dfrac{3^9\cdot5^9\cdot2^{18}\cdot3^{16}}{3^{15}\cdot2^{16}\cdot5^8}\\ =\dfrac{3^9\cdot5\cdot2^2\cdot3}{1\cdot1\cdot1}\\ =3^{10}\cdot5\cdot2^2\\ =59049\cdot5\cdot4\\ =59049\cdot\left(5\cdot4\right)\\ =59049\cdot20\\ =1180980\)
\(C=\dfrac{2^{10}\cdot10^{17}\cdot7^9}{5^{15}\cdot14^9\cdot64^9}\\ =\dfrac{2^{10}\cdot\left(2\cdot5\right)^{17}\cdot7^9}{5^{15}\cdot\left(2\cdot7\right)^9\cdot\left(2^6\right)^9}\\ =\dfrac{2^{10}\cdot2^{17}\cdot5^{17}\cdot7^9}{5^{15}\cdot2^9\cdot7^9\cdot2^{54}}\\ =\dfrac{2\cdot1\cdot5^2\cdot1}{1\cdot1\cdot1\cdot2^{37}}\\ =\dfrac{5^2}{2^{36}}\\ =\dfrac{25}{2^{36}}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a, (-45)+(-2018)+/-145/+/-2018/
=[(-45)+/-45/] +[(-2018)+/-2018/)
=(-45+45)+(-2018+2018)
=0
b, 5^3.4^3+85.5^3-5^7:5^4
=5^3.4^3+85.5^3-5^3
=5^3.(4^3+85-1)
=5^3.148
=18500
c, (7^108.50-7^108):7^110
=[7^108.(50-1)];7^110
=(49.7^108):7^110
=49:7^2
=49:49=1
a) (-45)+(-2018)+/-145/+/-2018/
=(-45)+(-2018)+145+2018
=(-45+145)+(-2018+2018)
=100+0
=100
b)53.42+85.53-57:54
=53.42+85.53-53
=53.(42+85-1)
=53.100
=12500
c) (7108.50-7108):7110
=7108.(50-1):7110
=7108.49:7110
=7108.72:7110
=7110:7110
=1
![](https://rs.olm.vn/images/avt/0.png?1311)
A = 0-1 + 2-3 + 4-5 +...+ 2017-2018
=> A = (-1) + (-1) + (-1) +...+ (-1) (Có 1009 số hạng)
=> A = 1009.(-1)
=> A = -1009
B = 1-3+5-7+ 9-11+....+2005-2007
=> B = (-2) + (-2) +(-2) +...+ (-2) (Có 502 số hạng)
=> B = 502.(-2)
=> B = -1004
C=1+2+3-4-5-6+7+8+9-10-11-12+.....+97+98+99-100-101-102
=> C = (1+2+3-4-5-6)+...+(97+98+99-100-101-102) (có 17 cặp số)
=> C = (-9) + (-9) +...+ (-9) (có 17 số hạng)
=> C = (-9).17
=> C = -153
![](https://rs.olm.vn/images/avt/0.png?1311)
1.
a, => 21-x+3 < 0
=> 24-x < 0
=> x < 24
b, => 7+x > 0
=> x > -7
c, => x-1 < 0 ; x+2 > 0 ( vì x-1 < x+2 )
=> x < 1 ; x > -2
=> -2 < x < 1
Tk mk nha
\(\left(-\frac{7}{4}\right)^2+\left(-\frac{3}{4}\right)^9.64-2018^0=\frac{49}{16}+\left(-\frac{19683}{262144}\right).64-1\)
\(=\frac{49}{16}-\frac{19683}{4096}-1\)\(=\frac{12544-19683-4096}{4096}\)
\(=-\frac{11235}{4096}\)