a, 257+149-57-49
b, 918-142-258
c,26,7-17,9+13.26-17.11
d,1754:17-74:17+20:17
Tính nhanh:
a) 47.29-13.29-24.29;
b) 26.7-17.9 + 13.26-17.11;
c) 1167:6 + 33:6;
d) 1754:17 - 74:17 + 20:17.
26.7-17.9+13.26-17.11
1167:67.33:6
1754:17-74+26:17
dấu chấm là nhân nhé giúp mình mình cần gấp lắm ạ
làm ơn
26.7-17.9+13.26-17.11=180
2con kia bạn lên xem lại đề bài
so sánh
a )3/124 ; 1/41 ; 5/207 ;2/84
b) 163 / 257 ; 163/221; 149/257
c) -15/18;-17/20;-21/24
giúp mk nhé
b: \(\dfrac{163}{257}< \dfrac{163}{221}\)
mà 149/257<163/257
nên 149/257<163/257<163/221
c: \(\dfrac{15}{18}=\dfrac{5}{6}=\dfrac{100}{120}\)
\(\dfrac{17}{20}=\dfrac{102}{120}\)
\(\dfrac{21}{24}=\dfrac{105}{120}\)
mà 100<102<105
nên 15/18<17/20<21/24
=>-15/17>-17/20>-21/24
Kết quả phép tính (-20)+(-37) A:17. ,B:-57 ,C:57 , D:-17
a, 57-63+43-17
b,(-257-265)-(135-257)
c,|x-11|=7
d,(3x-12)(x+31)=0
\(\left|x-11\right|=7\)
\(\Leftrightarrow\orbr{\begin{cases}x-11=7\\x-11=-7\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=18\\x=4\end{cases}}\)
d,\(\left(3x-12\right)\left(x+31\right)=0\)
\(\Rightarrow\orbr{\begin{cases}3x-12=0\\x+31=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=4\\x=-31\end{cases}}\)
Điền dấu >, <, = vào chỗ chấm
82 … 86 | 74 … 80 | 17 … 10 + 7 |
95 … 91 | 62 … 59 | 76 … 50 + 20 |
55 … 57 | 44 … 55 | 16 … 12 + 5 |
Lời giải chi tiết:
82 < 86 | 74 < 80 | 17 = 10 + 7 |
95 > 91 | 62 > 59 | 76 > 50 + 20 |
55 < 57 | 44 < 55 | 16 < 12 + 5 |
Tìm x:
a) (3x - 24) . 73 = 2 . 74
b) 5. (x - 3)2 + 17 = 142
c) [(6x - 72) : 2 - 84] . 28 = 5628
a) Xem lại đề.
b) 5. (x - 3)2 + 17 = 142
5. (x - 3)2 = 142 - 17
5. (x - 3)2 = 125
(x - 3)2 = 125 : 5
(x - 3)2 = 25
(x - 3)2 = 52 (cùng số mũ)
⇒ x - 3 = 5
x = 5 + 3 = 8
c) [(6x - 72) : 2 - 84] . 28 = 5628
[(6x - 72) : 2 - 84] = 5628 : 28
[(6x - 72) : 2 - 84] = 201
(6x - 72) : 2 = 201 + 84
(6x - 72) : 2 = 285
6x - 72 = 285. 2
6x - 72 = 570
6x = 570 + 72
6x = 642
x = 642 : 6
x = 107
D= ( 1374. 57+86. 687):(74. 14+13.26)
1) -145.(13 - 57) + 57.(10 -145)
2) 17.(15 - 16) + 16.( 17- 20)
3) -38.(25 - 4) + 25.(-4 + 38 )
4) 23.(145 - 17) - 145.(23 - 6)
5) 24.(15 - 4) + 4.(24 - 15)
6) 199.(15 - 17) - 199.(-17 + 5)
7) -39.(5 - 99) + 99.(10 - 39)
1: \(=-145\cdot13+145\cdot57+57\cdot10-57\cdot145=-1315\)
2: \(=17\cdot15-17\cdot16+16\cdot17-16\cdot20=255-320=-65\)
3: \(=-38\cdot25+38\cdot4-25\cdot4+25\cdot38=13\cdot4=52\)
4: \(=23\cdot145-23\cdot17-145\cdot23+145\cdot6=479\)
5: \(=24\cdot15-24\cdot4+4\cdot24-4\cdot15=360-60=300\)
6: \(=199\left(15-17+17-5\right)=199\cdot10=1990\)
7: \(=-39\cdot5+39\cdot99+99\cdot10-99\cdot39=795\)
1: =−145⋅13+145⋅57+57⋅10−57⋅145=−1315=−145⋅13+145⋅57+57⋅10−57⋅145=−1315
2: =17⋅15−17⋅16+16⋅17−16⋅20=255−320=−65=17⋅15−17⋅16+16⋅17−16⋅20=255−320=−65
3: =−38⋅25+38⋅4−25⋅4+25⋅38=13⋅4=52=−38⋅25+38⋅4−25⋅4+25⋅38=13⋅4=52
4: =23⋅145−23⋅17−145⋅23+145⋅6=479=23⋅145−23⋅17−145⋅23+145⋅6=479
5: =24⋅15−24⋅4+4⋅24−4⋅15=360−60=300=24⋅15−24⋅4+4⋅24−4⋅15=360−60=300
6: =199(15−17+17−5)=199⋅10=1990=199(15−17+17−5)=199⋅10=1990
7: =−39⋅5+39⋅99+99⋅10−99⋅39=795
17,65 < x < 18,01. Số tự nhiên x là:
A. 17 B. 17,9 C. 18 D. 19