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a) \(79.2^3+21.2^3\)
\(=\left(79+21\right).2^3=100.8\)
= 800
b) \(2.\left(6.4^2-85:5\right)\)
\(=2.\left(96-17\right)=2.79\)
= 158
c) (- 5) . 8 . (- 2) . 3
= \(\left[\left(-5\right).\left(-2\right)\right].\left(8.3\right)\)
= 10 . 24 = 240
d) 200 + 32 - (50 + 32)
= 200 + 32 - 50 - 32 (quy tắc mở ngoặc đổi dấu)
= 200 + (32 - 32) - 50
= 200 - 50 = 150
e) 3 . \(\left(-2\right)^2\) + 4 . (- 5) + 20
= 3 . 4 + 4 .(- 5) + 20
= 4 . (-2) + 20
= - 8 + 20 = 12
Chúc học tốt!!
a) 79. 23 + 21 . 23
= 79 . 8 + 21 . 8
= ( 79 + 21 ) . 8
= 100 . 8
= 800
b) 2. ( 6 . 42 - 85 : 5 )
= 2 . ( 6 . 16 - 17 )
= 2 . ( 96 - 17 )
= 2 . 17
= 34
c) (-5) . 8 . (-2) . 30
= (-40) . (-2) . 3
= 80 . 3
= 240
d) 200 + 32 - ( 50 + 32 )
= 232 - 82
= 150
e) 3. (-2)2 + 4. (-5) + 20
= 3. (-4) + 4 . ( -5) + 20
= (-12 ) + (-20) + 20
= (-12) + 0
= (-12)
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a) = 25 x 32 + 25 x 47 - 32 x 25 + 32 x 47
= 25 x 47 - 32 x 47
= -329
b) = 2 - 12 - 6
= -16
c) = 2 x (-7) - 10 + 1
= -14 - 10 + 1
= -23
d) = -6 - (-1) + (-2)
= -7
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(1981 x 1982 - 990) : (1980 x 1982 + 992)
=(1980 x 1982+1982 -990) : (1980 x 1982 +992)
=(1980 x 1982 + 992) : ( 1980 x 1982 + 992)
=1
B=[(45.79+45.21)]:90-5^2]:5+2^3 B=[(45.79+45.21):90-25]:5+8 B=[(45.(79+21):65]:13 B=[(45.100):65]:13 B=[4500:65]:13 B=4500:65:13
=8×25-2^5÷ 2^3
=200-2^2
=200-4
=196
2^3x5^2-32:2^3
=8x25-32:8
=200-4
=196
Chúc bạn hok tốt