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a)2x=64
2x=26
=>x=6
Vậy x =6
b)3x-1=81
3x-1=34
=>x-1=4
x=1+4
x=5
Vậy x=5
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Đặt A=1+2+22+...+220081+2+22+...+22008
=>2A=2.(1+2+22+...+220081+2+22+...+22008)
=>2A=2+22+23+...+220092+22+23+...+22009
=>2A-A=(2+22+23+...+220092+22+23+...+22009)-(1+2+22+...+220081+2+22+...+22008)
=>A=22009−122009−1
=>A=(-1).(−2)2009(−2)2009+(-1).1
=>A=(-1).[(−2)2009+1][(−2)2009+1]
=>A=(-1).(1−22009)(1−22009)
=>1+2+22+...+220081+2+22+...+22008/1-2200922009
=(−1).(1−22009)1−22009(−1).(1−22009)1−22009=-1
Giải:
Đặt A=1+2+22+23+...+22008
2A=2+22+23+24+...+22009
2A-A=(1+2+22+23+...+22008)-(2+22+23+24+...+22009)
A =1-22009
Vậy B=1-22009/1-22009=1
Chúc bạn học tốt!
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a) x + 22 + (-14) + 52 = x + 60
b) (-90) - (p + 10) + 100
= -90 - p - 10 + 100
= (-90 -10 + 100) -p = -p
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(1/32)^100 = ((1/2)^5)^100 = (1/2)^500
(1/16)^120 = ((1/2)^4)^120 = (1/2)^480
=> (1/32)^100 > (1/16)^120
(1/32)^100=0
(1/16)^120=0
nen (1/32)^100=(1/16)^100
k cho minh nha
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Ta gọi tử của phân số B là A ta có:
A=1+2+2^2+2^3+...+2^2008
2A=2 + 2^2 + 2^3 + 2^4 +... + 2^2009
=>A=2^2009 - 1
A=-1 + 2^2009
ta thấy tử là số đối của mẫu =>B=\(\dfrac{-1}{1}\)
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xy + x + y = -5
x(y + 1) + y = -5
x(y + 1) + y + 1 = -5 + 1 = -4
(x + 1)(y + 1) = -4 = -4.1 = -2.2 = -1.4
x + 1 = - 4 => x = -5 ; y+ 1 = 1 => y = 0
x + 1 = -2 => x = -3 ; y + 1 = 2 => y = 1
x + 1 = -1 => x = -2; y + 1 = 4 => y = 3
Vậy (x , y) = (-5 ; 0) ; (-2 ; 1) ; (-2 ; 3)
xy+x+y= -5
(x+1)y+x =-5
(x+1)y+x-(-5)=0
(X+1)y+x+5=0
x+1=0
x= -1
y+1=0
y= - 1
nhân 2 lên rồi lấy 2B - B thui
\(B=1+2+2^2+2^3+...+2^{2008}\)
\(2B=2+2^2+2^3+2^4+...+2^{2009}\)
\(2B-B=B=\left(2+2^2+2^3+2^4+...+2^{2009}\right)-\left(1+2+2^2+2^3+...+2^{2008}\right)\)
\(B=2^{2009}-1\)