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( 25 . 4 + 65 . 7 ) : 5 - 2 . ( 152 : 8 - 320 : 16 )
= ( 100 + 455 ) : 5 - 2 . ( 19 - 20 )
= 555 : 5 - 2 . ( -1 )
= 111 - ( -2 )
= 113
a: \(\dfrac{-3}{25}\cdot\dfrac{4}{17}\cdot\dfrac{5}{-3}\cdot\dfrac{17}{2}=\dfrac{4}{17}\cdot\dfrac{17}{2}\cdot\dfrac{3}{25}\cdot\dfrac{5}{3}=2\cdot\dfrac{1}{5}=\dfrac{2}{5}\)
b: \(=-\dfrac{8}{15}\cdot\dfrac{13}{16}\cdot\dfrac{30}{13}=\dfrac{-8}{15}\cdot\dfrac{15}{8}=-1\)
c: \(=\dfrac{3}{11}\left(\dfrac{2}{9}\cdot\dfrac{-8}{33}+\dfrac{7}{9}\right)=\dfrac{3}{11}\cdot\dfrac{215}{297}=\dfrac{2015}{1089}\)
a) (125 - x) + 25 = 98
125 - x = 98 - 25
125 - x = 73
x = 125 - 73
x = 52
b) 100 : (x + 20) = 68 : 34
100 : (x + 20) = 2
x + 20 = 100 : 2
x + 20 = 50
x = 50 - 20
x = 30
c) (3x + 12) . 5 = 25 . 4 - 10
(3x + 12) . 5 = 100 - 10
(3x + 12) . 5 = 90
3x + 12 = 90 : 5
3x + 12 = 18
3x = 18 - 12
3x = 6
x = 6 : 2
x = 3
d) 210 : (2x - 3) - 20 = 10
210 : (2x - 3) = 10 + 20
210 : (2x - 3) = 30
2x - 3 = 210 : 30
2x - 3 = 70
2x = 70 + 3
2x = 73
x = 73/2
a, ( 125 - x ) + 25 = 98
⇒ 125 - x = 73
⇒ x = 52.
Vậy..
b, 100 : ( x + 20 ) = 68 : 34
⇒ 100 : ( x + 20 ) = 2
⇒ x + 20 = 50
⇒ x = 30
Vậy...
c, ( 3 . x + 12 ) . 5 = 25 . 4 - 10
⇒ ( 3 . x + 12 ) . 5 = 90
⇒ 3 .x + 12 = 18
⇒ 3x = 6
⇒ x = 2.
Vậy...
d, 210 : ( 2 .x - 3 ) - 20 = 10
⇒ ( 2 .x - 3 ) - 20 = 21
⇒ 2x - 3 = 41
⇒ 2x = 44
⇒ x = 22.
Vậy..
\(\Leftrightarrow20+8\left(x+3\right)=100\\ \Leftrightarrow8\left(x+3\right)=80\\ \Leftrightarrow x+3=10\\ \Leftrightarrow x=7\)
1) x - 18 : 3 = 12
x - 6 = 12
x = 12 + 6
x = 18
2) ( x : 3 ) - 18 = 12
x : 3 = 12 + 18
x : 3 = 30
x = 30 x 3
'x = 90
3) ( x - 3 ) : 4 = 7
x - 3 = 7 x 4
x - 3 = 28
x = 28 + 3
x = 31
4 ) ( x : 15 ) - 3 = 25 x 4
( x : 15 ) - 3 = 100
x : 15 = 100 + 3
x : 15 = 103
x = 103 x 15
x = 1545
5) ( x - 25 ) : 9 = 0
x - 25 = 0 x 9
x - 25 = 0
x = 0 + 25
x = 25
6) 34 : ( x - 8 ) = 34
x - 8 = 34 : 34
x - 8 = 1
x = 1 + 8
x = 9
7) ( x + 4 ) x 16 = 80
x + 4 = 80 : 16
x + 4 = 5
x = 5 - 4
x = 1
a) 125 . 10 = 1 250
b) 2 021 . 100 = 202 100
c) 1 991 . 25 . 4 = 1 991 . (25 . 4) = 1 991 . 100 = 199 100
d) 3 025 . 125 . 8 = 3 025 . (125 . 8)
= 3 025 . 1 000 = 3 025 000
a) \(4.3^4-16:2^2+2.5^3\)
\(=4.81-16:4+2.125\)
\(=324-4+250\)
\(=570\)
b) \(100:\left\{250:\left[450-\left(4.5^3-25.4\right)\right]\right\}\)
\(=100:\left\{250:\left[450-\left(500-100\right)\right]\right\}\)
\(=100:\left\{250:\left[450-400\right]\right\}\)
\(=100:\left\{250:50\right\}\)
\(=100:5\)
\(=20\)
nhớ là 3 k nhá
a) 4.3^4-16:2^2+2.5^3
= 4.81-16:4+2.125
= 324-4+250
= 320+250
= 570
b)100:{250:[450-(4.5^3-25.4)]}
= 100:{250:[450-(4.125-100)]}
= 100:{250:[450-(500-100)]}
= 100:{250:[450-400]}
= 100:{250:50}
= 100:5
= 20
nhớ đúng cho mình nha
a) \(18+25\times4-4^3\)
\(=18+100-64\)
\(=118-64\)
\(=54\)
b) \(275-\left(49+125\div5^3\right)\)
\(=275-\left(49+125\div125\right)\)
\(=275-\left(49+1\right)\)
\(=275-49-1\)
\(=226-1\)
\(=225\)
c) \(2015+\left(8\times15-\left(18-8\right)^2\right)\)
\(=2015+\left(8\times15-\left(10\right)^2\right)\)
\(=2015+\left(8\times15-100\right)\)
\(=2015+\left(120-100\right)\)
\(=2015+20\)
\(=2035\)
tính hợp lý nếu có thể
a) 2.25.9.4
b)35.112-12.35+50
c)16+(516 : 514 - 90)
d) 24.7 - [181 - ( 13 - 4)2 ]
a: \(2\cdot25\cdot9\cdot4=25\cdot4\cdot9\cdot2=18\cdot100=1800\)
b: \(35\cdot112-12\cdot35+50\)
\(=35\left(112-12\right)+50\)
=3500+50
=3550
c: \(16+\left(5^{16}:5^{14}-9^0\right)\)
\(=16+5^2-1\)
=25+15
=40
d: \(24\cdot7-\left[181-\left(13-4\right)^2\right]\)
\(=168-181+9^2\)
=81-13
=68
a)2.25.9.4
=(25.4).(9.2)
=100.18
1800
b)35.112-12.35+50
=35.(112-12)+50
=35.100+50
=3500+50
=3550
c)\(16+\left(5^{16}:5^{14}-9^0\right)\)
\(=16+\left(5^2-9^0\right)\)
\(=16+\left(25-1\right)\)
\(=16+24\)
\(=40\)
d)\(24.7-[181-\left(13-4\right)^2]\)
\(=24.7-[181-9^2]\)
\(=24.7-[181-81]\)
\(=24.7-100\)
\(=168-100\)
\(=68\)
\(\left[516-\left(25\cdot4+16\right)\right]:8-68\)
\(=\dfrac{\left[516-100-16\right]}{8}-68\)
\(=\dfrac{400}{8}-68=50-68=-18\)