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a. {[(2:x + 14) : 22 - 3] : 2} - 1 = 0
[(2:x + 14) : 4 - 3] : 2 = 1
(2:x + 14) : 4 - 3 = 2
(2:x + 14) : 4 = 5
2:x + 14 = 20
2:x = 6
x = 2:6
x = 1/3
b. 10 - {[(x:3 + 17) : 10 + 3.16] : 10} = 5
[(x:3 + 17) : 10 + 48] : 10 = 5
(x:3 + 17) : 10 + 48 = 50
(x:3 + 17) : 10 = 2
x:3 + 17 = 20
x:3 = 3
x = 9
2.
a,. 1619 = (24)19 = 276
825 = (23)25 = 275
Vì 276 > 275 nên 1619 > 825
b. 2711 = (33)11 = 333
818 = (34)8 = 332
Vì 333 > 332 nên 2711 > 818
a) 27^16 : 9^10
Ta có: (3.9)^16 : 9^10
= 3^16.9^16: 9^10
= 3^16. 9^6
= 3^16.(3^2)^6
=3^16.3^12
=3^28
Bài 1 :
a) 1440 : [ 41 - (2x - 5)] = 24.3
=> 1440 : [41 - (2x - 5)] = 16.3
=> 1440 : [41 - (2x - 5)] = 48
=> 41 - (2x - 5) = 1440 : 48 = 30
=> 2x - 5 = 11
=> 2x = 16
=> x = 8
b) 5 . [225 - (x - 10)] - 125 = 0
=> 5 . [225 - (x - 10)] = 125
=> 225 - (x - 10) = 125 : 5
=> 225 - (x - 10) = 25
=> x - 10 = 200
=> x = 210
Bài 2 :
a) [ 545 - (45 + 4.25)] : 50 - 200 : 250 + 215 : 213
= [ 545 - (45 + 100)] : 50 - 4/5 + 22
= [545 - 145] : 50 - 4/5 + 4
= 400 : 50 - 4/5 + 4 = 8 - 4/5 + 4 =56/5
Mấy câu còn lại tương tự
Bài 1.
a, 1440:[41-(2x-5)]=24.3
1440:[41-(2x-5)]= 16.3
1440:[41-(2x-5)]=48
[41-(2x-5)] =1440:48
[41-(2x-5)] = 30
2x-5 = 41-30
2x-5 =11
2x = 11+5
2x = 16
x = 16:2
x =8
b, 5.[225-(x-10)]-125=0
5.[225-(x-10)] =125
[225-(x-10)] =125:5
[225-(x-10)] = 25
(x-10) = 225-25
(x-10) = 200
x =200+10
x = 210
Bài 2.
a, [545-(45+4.25)]:50-200:250+215:213
= [545-(45+100)]:50-200:250+22
= [545-145]:50- 200:250+4
= 400:50-200:250+4
= 8-0,8+4
= 7,2 + 4
= 11,4
b, [504-(25.8+70)]:9-15+190
= [504-(200+70)]:9-15+1
= [504-270]:9-16
= 234:9-16
= 26-16
= 10
c, 5.{26-[3.(5+2.5)+15]:15}
= 5.{26-[3.(5+10)+15]:15}
= 5.{26-[3.15+15]:15}
= 5.{26-[45+15]:15}
= 5.{26-60:15}
= 5.{26-4}
=5.22
= 110
d,[1104-(25.8+40)]:9+316:312
= [1104-(200+40)]:9+34
=[1104-240]:9+34
=864:9+81
=96+81
=177
hok tốt
1,2 dễ ko làm
3,
S = 1 + 2 + 22 + 23 + ... + 29
2S = 2 + 22 + 23 + 24 + ... + 210
2S - S = ( 2 + 22 + 23 + 24 + ... + 210 ) - ( 1 + 2 + 22 + 23 + ... + 29 )
S = 210 - 1
Mà 5 . 28 = ( 1 + 22 ) . 28 = 28 + 210 > 210 > 210 - 1
Vậy S < 5 . 28
P = 1 + 3 + 32 + 33 + ... + 320
3P = 3 + 32 + 33 + 34 + ... + 321
3P - P = ( 3 + 32 + 33 + 34 + ... + 321 ) - ( 1 + 3 + 32 + 33 + ... + 320 )
2P = 321 - 1
P = ( 321 - 1 ) : 2 < 321
Vậy P < 321
a: \(=-25\cdot4-27=-100-27=-127\)
b: \(=-65:\left(-13\right)-25\cdot4=5-100=-95\)
c: \(=100\cdot\left(-47\right)+53\cdot\left(-100\right)=100\cdot\left(-100\right)=-10000\)
d: \(=\left[\left(-3\right)^{13}:3^{10}-73\right]:\left(-5\right)^2-14\)
\(=\left(-100\right):25-14=-4-14=-18\)
Bài 1:
a, \(\left(3x-1\right)^3=27=3^3\)
\(\Rightarrow3x-1=3\Rightarrow3x=4\Rightarrow x=\dfrac{4}{3}\)
b, \(2^{x-2}=16=2^{4^{ }}\)
\(\Rightarrow x-2=4\Rightarrow x=6\)
c, \(3^x=9.27=3^2.3^3=3^5\)
\(\Rightarrow x=5\)
d, \(15x-899:29=194\)
\(15x-31=194\Rightarrow15x=225\Rightarrow x=15\)
Bài 2:
a, \(5^2.3^2-32:2^{2^{ }}\)\(=15^2-2^5:2^2=225-8=217\)
b, \(19.37+63.19-400\)\(=19.\left(37+63\right)-400=19.100-100.4=100.\left(19-4\right)\)
\(=100.15=1500\)
c, 205-\(\left\{102-\left[48-\left(16-14\right)^{ }3\right]\right\}\)\(=205-\left\{102-\left[48-2^3\right]\right\}=205-\left(102-40\right)\)
\(=205-62=143\)
thanks....