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a) 5X-2-32=24-( 28 .24-210.22)
5X-2-9=16-( 28+4-210+2)
5X-2-9=16-( 212-212)
5X-2-9=16-0
5X-2-9=16
5X-2=16+9
5X-2=25
5X-2=52
=>x-2=2
x=2+2
x=4
b)697 :[ ( 15 .x+ 64) :x]=17
k biết
c) 134: ( x-3 )= 35+ 160:5
134: ( x-3 )= 35+32
134: ( x-3 )= 67
x-3=134:67
x-3=2
x=2+3
x=5
d) ( 3. x - 24) .73-2.74
đề thiếu
e) [(10-x).2-5 ] : 3-2=3
[(10-x).2-5 ] : 3=3+2
[(10-x).2-5 ] : 3=5
(10-x).2-5=5x3
(10-x).2-5=15
(10-x).2=15+5
(10-x).2=20
10-x=20:2
10-x=10
x=10-10
x=0
Dãy số có 2 chữ số chia hết cho 3 là:[12,15,....,99]
Khoảng cách của từng số hạng là 3
Số số hạng là: (99-12):3+1=30(số)
Vậy có 30 số có 2 chữ số chia hết cho 3
a: \(\Leftrightarrow\left[\left(3x+14\right):4-3\right]:2=1\)
=>(3x+14):4-3=2
=>(3x+14):4=5
=>3x+14=20
=>3x=6
hay x=2
b: \(\Leftrightarrow\left[\left(x:4+17\right):10+3\cdot16\right]:10=5\)
\(\Leftrightarrow\left(x:4+17\right):10=50-48=2\)
=>x:4+17=20
=>x:4=3
hay x=12
c: \(\Leftrightarrow2\cdot15^2+\left[2\cdot125-\left(2x+4\right)\cdot5\right]:19=453\)
\(\Leftrightarrow250-\left(2x+4\right)\cdot5=\left(453-450\right)\cdot19=57\)
=>5(2x+4)=197
=>2x+4=197/5
=>2x=177/5
hay x=177/10
d: \(\Leftrightarrow\left(19x+50\right):14=5^2-4^2=9\)
=>19x+50=126
=>19x=76
hay x=4
e: \(\Leftrightarrow2\cdot3^x=10\cdot3^{12}+8\cdot3^{12}=18\cdot3^{12}\)
\(\Leftrightarrow3^x=3^2\cdot3^{12}=3^{14}\)
hay x=14
f: \(\Leftrightarrow3\left(x+2\right):7=30\)
=>3(x+2)=210
=>x+2=70
hay x=68
g: \(2480-1570+200-x+5=1010\)
=>1115-x=1010
hay x=105
a; -2\(x\) - 3.(\(x-17\)) = 34 - 2.( - \(x\) + 25)
- 2\(x\) - 3\(x\) + 51 = 34 + 2\(x\) - 50
2\(x\) + 2\(x\) + 3\(x\) = - 34 + 50 + 51
7\(x\) = 67
\(x\) = 67 : 7
\(x\) = \(\dfrac{67}{7}\)
Vậy \(x\) = \(\dfrac{67}{7}\)
b; 17\(x\) + 3.(- 16\(x\) - 37) = 2\(x\) + 43 - 4\(x\)
17\(x\) - 48\(x\) - 111 = 2\(x\) - 4\(x\) + 43
- 31\(x\) - 2\(x\) + 4\(x\) = 111 + 43
- \(x\) x (31 + 2 - 4) = 154
- \(x\) x (33 - 4) = 154
- \(x\) x 29 = 154
- \(x\) = 154 : (-29)
\(x\) = - \(\dfrac{154}{29}\)
Vậy \(x=-\dfrac{154}{29}\)
a) 57 . 53 : 510 = 510 : 510 = 1
b) 24 : 23 . 27 = 2 . 27 = 28
c) 93 : 33 . 272 = ( 32 ) 3 : 33 . ( 33 ) 2 = 36 : 33 . 36 = 33 . 36 = 39
d) 25 . 13 - 25 . 5 = 25 . ( 13 - 5 ) = 25 . 8 = 25 . 23 = 28
e) \(\frac{4^6.8^3}{4^8}=\frac{\left(2^2\right)^6.\left(2^3\right)^3}{\left(2^2\right)^8}=\frac{2^{12}.2^9}{2^{16}}=\frac{2^{21}}{2^{16}}=2^5\)
a,71.2-6.(2x+5)=10^5:10^3
142-6.(2x+5)=10^2
142-6.(2x+5)=100
6.(2x+5)=142-100
6.(2x+5)=42
2x+5=42:6
2x+5=7
2x=7-5
2x=2
x=1
Vậy x=1
, thứ 4 là kiểm tra 90'p rồi
Bài 1:
a) 12.18 + 14.3 - 255 : 17
= 216 + 42 - 15
= 258 - 15
= 243
b) 15.8 - (83 - 30 + 17) - 144 : 6
= 15.8 - (53 + 17) - 144 : 6
= 15.8 - 70 - 144 : 6
= 120 - 70 - 144 : 6
= 120 - 70 - 24
= 50 - 24
= 26
c) 24.(15 + 30 + 85 - 120) : 10
= 24.(45 + 85 - 120) : 10
= 24.(130 - 120) : 10
= 24.10 : 10
= 24.1
= 24
d) 15 - 25.8 : (100.2)
= 15 - 25.8 : 200
= 15 - 200 : 200
= 15 - 1
= 14
e) 32.5 - 22.7 + 1.5
= 9.5 - 4.7 + 1.5
= 45 - 28 + 5
= 17 + 5
= 22
g) (24.5 - 52.2) : (5.2) - 3
= (24.5 - 25.2) : (5.2) - 3
= (120 - 50) : 10 - 3
= 70 : 10 - 3
= 7 - 3
= 4
h) [(52.23 - 72.2) : 2].6 - 7.25
= [(25.8 - 49.2) : 2].6 - 7.32
= [(200 - 98) : 2].6 - 224
= [102 : 2].6 -224
= 51.6 - 224
= 306 - 224
= 82
i) 27 : 22 + 54 : 53.24 - 3.25
= 25 + 5.24 - 3.25
= 32 + 5.16 - 3.32
= 32 + 80 - 96
= 112 - 96
= 16
k) (37.35) : 310 + 5.24 - 73 : 7
= 312 : 310 + 5.24 - 72
= 32 + 5.24 - 72
= 9 + 5.16 - 49
= 9 + 80 - 49
= 89 - 49
= 40
Bài 2:
a) 547 + 389 + 453 + 211
= (547 + 453) + (389 + 211)
= 1000 + 600
= 1600
b) 125.98.2.8.25
= (125.8).(25.2.98)
= 1000.4900
= 4900000
c) 8466.15 + 170.4233
= 4233.2.15 + 170.4233
= 4233.30 + 170.4233
= 4233.(30 + 170)
= 4233. 200
= 846600
d) (62007 - 62006) : 62006
= 62007 : 62006 - 62006 : 62006
= 6 - 1
= 5
e) (112003 + 112002) : 112002
= 112003 : 112002 + 112002 : 112002
= 11 + 1
= 12
f) 4.24.52 - (33.18 + 33.12)
= 4.24.25 - [33.(18 + 12)]
= 4.25.24 - [27.30]
= 100.24 - 810
= 2400 - 810
= 1590
g) 23.7.53- (52.65 + 52.35)
= 8.7.125 - (25.65 + 25.35)
= 8.125.7 - [25.(65 + 35)]
= 1000.7 - [25.100]
= 7000 - 2500
= 4500
Xin lỗi nha, nhìu quá mk lm ko hết, thông cảm cho mk.
c) 134 : ( x - 3 ) = 35 + 160 : 5
<=> 134 : ( x - 3 ) = 67
<=> x - 3 = 134 : 67
<=> x - 3 = 2
<=> x = 2 + 3
<=> x = 5
c) 134 : ( x - 3 ) = 35 + 160 : 5
134 : ( x - 3 ) = 35 + 32
134 : ( x - 3 ) = 67
( x - 3 ) = 134 : 67
x - 3 = 2
x = 2 + 3
x = 5