a) 20.[32+(134−80):27]−120b) 1−7+13−19+⋯−103+107c) A = 491(267 + 53) –491.153 –491.67; d) B = (29.3 + 29.5) : 210
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a) 491 x (267+53) - 491 x ( 153 + 67 )
=491x<(267+53) - (153+67)>
=491x<300-200>
=491x100
=49100
b) 53 x 39 + 47 x 39 - 53 x 21 - 47 x 21
=53x(39-21) - 47x(39-21)
=53x18-47x18
=18x(53-47)
=18x6
=108
bạn ơi cho mình sửa phần b) nha
b) 53 x 39 + 47 x 39 - 53 x 21 - 47 x 21
=53x(39-21) + 47x(39-21)
=53x18+47x18
=18x(53+47)
=18x100
=1800
a, 71.2 – 6.(2x+5) = 10 5 : 10 3
71.2 – 6.(2x+5) = 10 2
6.(2x+5) = 71.2 – 100
6.(2x+5) = 42
x = 1
b, 5 x + 3 4 . 6 8 = 6 9 . 3 4
5 x + 3 4 . 6 8 = 6 8 . 6 . 3 4
5 x + 3 4 = 6 8 . 6 . 3 4 : 6 8 = 6 . 3 4
5x = 6 . 3 4 - 3 4 = 5 . 3 4
x = 3 4
c, 12:{390:[5. 10 2 – ( 5 3 + x . 7 2 )]} = 4
390:[5. 10 2 – ( 5 3 + x . 7 2 )] = 12:4 = 3
5. 10 2 – ( 5 3 + x . 7 2 ) = 390:3 = 130
5 3 + x . 7 2 = 5. 10 2 – 130 = 370
x . 7 2 = 370 – 5 3 = 245
x = 245: 7 2 = 5
d, 5 3 .(3x+2):13 = 10 3 : 13 5 : 13 4
5 3 .(3x+2):13 = 10 3 : 13
3x+2 = 10 3 : 13 : 5 3 .13 = 8
x = 2
491.(267+53) + 491.(151+67) = 491.(267+53+151+67)
= 491 . 538
= 264158
\(491.\left(267+53\right)-491.\left(153+67\right)\)
\(=491.\left[267+53-125-67\right]\)
\(=491.100=49100\)
491.(267+53)-491.(153+67)=491.(267+53-153-67)=491.100=49100
1: =-2/9(15/17+2/17)=-2/9
2: \(=\dfrac{-6}{3}+\dfrac{-21}{90}\)
=-2-7/30=-67/30
3: \(=\dfrac{3}{4}\cdot\dfrac{7}{5}+\dfrac{9}{7}\cdot\dfrac{3}{2}\)
=21/20+27/14=417/140
4: =-25/13(5/19+14/19)=-25/13
5: =-7/5-45/21=-7/5-15/7=-124/35
1: =-2/9(15/17+2/17)=-2/9
2: =−63+−2190=−63+−2190
=-2-7/30=-67/30
3: =34⋅75+97⋅32=34⋅75+97⋅32
=21/20+27/14=417/140
4: =-25/13(5/19+14/19)=-25/13
5: =-7/5-45/21=-7/5-15/7=-124/35
a) 93.85+17.45-170=8500
b) 491.(267+53) -491. (153+67) =49100
c) 45.48-90.24+145=145
d) 754.75-2262.25+4568=4568
e) 23.157+15.46 -23.87=2300
a) A = { 1 + 3x ; 0 \(\le\)x \(\le\)6 }
b) B = { x3 ; 1 \(\le\)x \(\le\)5 }
c) C = { x ( x + 1 ) ; 1 \(\le\)x \(\le\)6 }