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=27.15-27.12-15.27+15.12
=-27.12+15.12
=12.(-27+15)
=12.(-12)
=-144
Cách 2
=27.3-15.15
=81-225
=-144
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mình biết làm câu D thôi còn câu còn lại chắc bạn ghi sai đề
\(D=\frac{4^7.2^8}{3.2^{15}.16^2-5.2^2.\left(2^{10}\right)^2}=\frac{2^{14}.2^8}{3.2^{15}.\left(2^4\right)^2-5.2^2.2^{20}}=\frac{2^{22}}{3.2^{15}.2^8-5.2^22^{20}}=\frac{2^{22}}{3.2^{22}.2-5.2^{22}}\)
\(=\frac{2^{22}}{2^{22}\left(3.2-5\right)}=\frac{2^{22}}{2^{22}.1}=1\) bạn ơi dấu . là nhân nhé
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27.(15-12)-15.(27-12)
= 27.15 - 27.12 - 15.27 - 15.12
= (27.15-15.27) - 12.(27-12)
= 0 - 12.15
= 180
27 ( 15 - 12 ) - 15 ( 27 - 12 )
= 27 . 15 - 27 . 12 - 15 . 27 + 15 . 12
= 27 . 15 - 15 . 27 - 27 . 12 + 15 . 12
= 0 - 27 . 12 + 15 . 12
= 12 . ( - 27 + 15 )
= 12 . ( - 12 )
= - 144
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g) (15 + 37) + (52 – 37 – 17) = 15 + 37 + 52 – 37 – 17 = 15 + 52 – 17 = 50 h) (38 – 42 +14) - (38 – 42 - 15) = 38 – 42 +14 - 38 + 42 + 15 = 14 + 15 = 29 i) (27 + 65 ) + (346 - 27- 65) = 27 + 65 + 346 - 27- 65 = 346 k) - (27 + 65) - (346 – 27 - 65) = -27 - 65 - 346 + 27 + 65 = -346 l) (42 – 69 + 17) - (42 + 17) = 42 – 69 + 17 - 42 - 17 = – 69 m) 24. (16 - 5) – 16. (24 – 5 ) = 24. 16 - 24 . 5 - 16 . 24 + 16. 5 = - 24 . 5 + 16. 5 = -8 . 5 = -40 n) (-12). 47 – 12 . 52 + (-12) = -12 (47 - 52 + 1) = -12 . (-4) = 48 p) 51 . (69 - 25) – 69. (51 - 25) = 51 . 69 - 51 . 25 – 69. 51 + 69. 25 = - 51 . 25 + 69. 25 = (- 51+ 69).25 = 450 |
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\(b)4\cdot(-5)^2+2\cdot(-5)-20\)
\(=4\cdot25+2\cdot(-5)-20\)
\(=100+(-10)-20=70\)
\(c)27\cdot(15-12)-15\cdot(27-12)\)
\(=27\cdot15-27\cdot12-15\cdot27-15\cdot12\)
\(=(27\cdot15-15\cdot27)-27\cdot12-15\cdot12\)
\(=0-(27-15)\cdot12=0-12\cdot12=0-144=-144\)
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a)(-45).312-312-54.312
=312.[(-45)-1-54]
=312.(-100)
=-31200
b)217.(-46)-217.15-217.40+27
=217.[(-46)-15-40]+27
=217.(-101)+27
=217.[(-100)+(-1)]+27
=-21700+(-217)+27
=-21700+(-190)
=-21890
-43.15+43.48-48.43+48.15
=(-43.15+48.15)-(43.48-48.43)
=5.15-0=75
27.(15-12)-15.(27-12)
= 27 . 15 - 27 . 12 - 15 . 27 - 15 . 12
= ( 27 . 15 - 15 . 27 ) - 12. ( 27 - 12 )
= 0 - 12 . 5
= 0 - 60
= -60
27.(15-12)-15.(27-12)
= 27.15- 27.12 - 15.27 - 15.12
= 27 ( 15-15) - 12( 27-15)
= 27.0 - 12.12
= 0 - 144
= -144