Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
A = 136 . 25 + 75 . 136 - 62 . 102 B = 90 - (22 . 25 - 32 . 7) C = 720 - {96 . [ (24 . 2 - 5) : 32 . 130] }
= 136 . (25 + 75) - 36 . 100 = 90 - (4 . 25 - 9 . 7)
= 136 . 100 - 36 . 100 = 90 - (100 - 63)
= (136 - 36) . 100 = 90 - 37
= 100 . 100 = 53
= 10000
D = 570 + {96 . [ (24 . 2 - 5) : 32 . 130] } E = 37 . 24 + 37 . 76 + 63 . 79 + 21 . 63
= 570 + {96 . [ (16 . 2 - 5) : 9 . 1] } = 37 . (24 + 76) + 63 . (79 + 21)
= 570 + [96 . (27 : 9) ] = 37 . 100 + 63 . 100
= 570 + (96 . 3) = (37 + 63) . 100
= 570 + 288 = 100 . 100
= 858 = 10000
a) 50+3x(25-16)2+150
=50+3x92+1
=50+3x81+1
=50+243+1
=294
b)22x52-35/32
=(2x5)2-35-2
=102-33
=100-27
=73
c)80-[130-(12-4)2 ]
=80-[130-82 ]
=80-[130-64]
=80-66
=14
d)100:[2x(52-35-8)]
=100:[2x9]
=100:18
=100/18
e)24:{300:[375-(150+15x5)]}
=24:{300:[375-(150+75)]}
=24:{300:[375-225]}
=24:{300:50}
=24:6
=4
s1=1+2+3+...+99
s1=99+98+...+1
2s1=100+100+....+100
2s1=100.99
s1=100.99:2=4950(mấy bài sau lam tương tự nha)
4+4^2+4^3+...+4^90 chia hết cho 21
=(4+4^2+4^3)+...+(4^88+4^89+4^90)
=84.1+(4^4+4^5+4^6+...+4^90)
vì 84 chia hết cho 21 suy ra tổng trên chia hét cho 21 (ĐPCM)
A, (-25). 21. (-2)2. (-|-3|). (-1)2015
B, (-5)3. 67. (-|-2|). (-1)2014
C, 35.18 – 5.7.28 + 35. (-90)
D, 24. (16 – 5) – 16. (24 – 5)
E, - 79. (73 – 27) – 73. (-79 + 27)
G, 31. (-18) + 31. (-8)-31
M, -48 + 48. (-78) + 48. (-21)
N, -|-17| + 2. [ 24: (-8) + (-5)2]
I, -|-7|. [(-2)4 + (-36): (-32)] – (-5)3
Bài 1: Thực hiện phép tính
a) 165 - [ 120 - ( 9 - 4 )2 ]
b) 32 : { 160 : [ 300 - ( 175 + 21 . 5 ) ] }
c) 6 . 52 - 32 : 24 + 32
d) 42 .37 - 42 . 33 + 24
Bài làm:
a) 165 - [ 120 - ( 9 - 4 )2 ]
= 165 - [ 120 - 52 ]
= 165 - [ 120 - 25 ]
= 165 - 95
= 70.
b) 32 : { 160 : [ 300 - ( 175 + 21 . 5 ) ] }
= 32 : { 160 : [ 300 - ( 175 + 105) ] }
= 32 : { 160 : [ 300 - 280 ] }
= 32 : { 160 : 20 }
= 32 : 8
= 4.
c) 6 . 52 - 32 : 24 + 32
= 6 . 25 - 32 : 16 + 9
= 150 - 2 + 9
= 148 + 9
= 157.
d) 42 .37 - 42 . 33 + 24
= 16. ( 37 - 33)
= 16 . 4
= 64.
Bài 2: Tìm số tự nhiên x, biết:
a) 91-5 . ( 5 + x ) = 61
b) ( x + 34 ) - 40 = 28
c) 3 . ( x -2 ) + 150 = 240
d) 360 : ( x- 7) = 90
e) 2448 : [ 119 - ( x - 6) ] = 24.
Bài làm:
a) 91-5 . ( 5 + x ) = 61
5 . ( 5 + x) = 91 - 61
5. ( 5+ x) = 30
5 +x = 30 : 5
5 +x = 6
x = 6 - 5
x = 1.
b) ( x + 34 ) - 40 = 28
x+ 34 = 40 + 28
x+ 34 = 68
x = 68 - 34
x = 34.
c) 3 . ( x - 2 ) + 150 = 240
3 . ( x - 2 ) = 240 - 150
3 . ( x - 2 ) = 90
x - 2 = 90 : 3
x - 2 = 30
x = 30 + 2
x = 32.
d) 360 : ( x - 7 ) = 90
x - 7 = 360 : 90
x - 7 = 4
x = 4 + 7
x = 11.
e) 2448 : [ 119 - ( x - 6 ) ] = 24
[ 119 - ( x - 6 ) ] = 2448 : 24
[ 119 - ( x - 6 ) ] = 102
x - 6 = 119 + 102
x - 6 = 221
x = 221 + 6
x = 227.
********************************Chúc bạn học tốt***********************************
a) ( x-140):7=33 -23 -3
(x-140):7 = 27 - 8-3
(x-140):7 = 16
(x-140):7 = 16 .7
x-140 = 112
x-140 = 112+ 140
x = 252
a.17 . 85 + 25 . 17 + 1200
=17.(85+25)+1200
=17.110+1200
=1870+1200
=3070
b.62 : 4 . 3 + 2 . 52
=36:4.3+2.25
=27+50
=77
c.5 . 42 - 18 : 32
=5.16-18:9
=80-2
=78
d.3 . 52 - 16 : 23 + 34 : 33
=3.25-16:8+3
=75-2+3
=76
e.220 - [ 32 . 33 - ( 12 - 70 ) 2]
=220-35+112
=220-243+121
=98
j. 49 . 73 + 49 . 51 - 49 . 24
=49.(73+51-24)
=49.100
=4900
Con bấm mỏi suốt đấy mấy má
nhầm
a) 17 . 85 + 25 . 17 + 1200
=(17.85+25.17)+1200
=17(85+25)+1200
=17.110+1200
=1870+1200
=3070
b) 62 : 4 . 3 + 2 . 52
=36:4.3+2.25
=9.3+50
=27+50
=77
c) 5 . 42 - 18 : 32
=5.16-18:9
=80-2
=78
d) 3 . 52 - 16 : 23 + 34 : 33
=3.25-24:23+3(4-3)
=75-2(4-3)+31
=75-21+3
=75-2+3
=76
e) 220 - [ 32 . 33 - ( 12 - 70 ) 2 ]
=220-[3(2+3)-(12-1)2]
=220-(35-112)
=220-(243-121)
=220-122
=98
j) 49 . 73 + 49 . 51 - 49 . 24
=49(73+51-24)
=49.100
=4900
c: \(24:\left\{300:\left[350-\left(175+25\right)\right]\cdot102\right\}\)
\(=\dfrac{24}{300:\left(350-200\right)\cdot102}\)
\(=\dfrac{24}{300:150\cdot102}=\dfrac{24}{204}=\dfrac{2}{17}\)
d: \(6:2\cdot3+4\cdot79-2\cdot5\)
\(=9-10+316\)
=316-1
=315
\(C)24:\left\{300:\left[350-\left(175+25\right)\right]\cdot102^0\right\}\)
\(=24:\left[300:\left(350-200\right)\cdot1\right]\)
\(=24:\left(300:150\right)\)
\(=24:2\)
\(=12\)
\(D)6^2:2\cdot3+4^2\cdot79-2^3\cdot5\)
\(=36:2\cdot3+16\cdot79-8\cdot5\)
\(=54+1264-40\)
\(=1278\)