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a) 27 x 39 + 27 x 63 - 2 x 2
= 27 x ( 39 + 63 ) - 2 x 2
= 27 x 102 - 2 x 2
= 2754 - 4
= 2750
b) 48 x 19 + 48 x 115 + 134 x 52
= 48 x ( 19 +115 ) + 134 x 52
= 48 x 134 + 134 x 52
= ( 48 + 52 ) x 134
= 100 x 134
= 13400
chúc các bạn năm mới vui vẻ. bạn tk mk nha.
a) 27 x 39 + 27 x 63 - 2 x 2
= 27 x (39 + 63) - 2 x 2
= 27 x 102 - 2 x 2
= 2754 - 4
= 2750
b) 48 x 19 + 48 x 115 + 134 x 52
= 48 x (19 + 115) + 134 x 52
= 48 x 134 + 134 x 52
= 134 x (48 + 52)
= 134 x 100
= 13400
a) \(\frac{1}{81}\): 3x = \(\frac{1}{729}\)
3x = \(\frac{1}{81}\): \(\frac{1}{729}\)
3x = 9
=> x = 2 ( vì 32 = 9 )
1. a, 15-(3+x)+2x=19
=> 15- 3 - x + 2x = 19
=> -x + 2x = 19 - 15 +3
=> ( -1 + 2 )x = 7
=> x = 7
b, (-58)-(19-58-x)=60
=> (-58)-(-39-x)=60
=> -58 +39 + x = 60
=> -19 + x = 60
=> x = 60 - (-19) = 79
c, 2(x-4)-3(x+5)=4
=> (2x - 8 )-(3x+15)= 4
=> 2x - 8 - 3x - 15 = 4
=> 2x - 3x = 4 + 15 + 8
=> - x = 27
=> x = -27
d, (2-3x)+(x-3)=(5x-1)-(5x-2)
=> 2 - 3x + x - 3 = 5x - 1 - 5x + 2
=> 2 - 3 - 3x + x = 5x - 5x - 1 +2
=> 2 - 3 - 3x + x = 1
=> - 3x + x = 1 - 2 + 3
=> -2x = 2
=> x= -1
=))))
giúp mk vs các bn ui, mai mk nộp bài rùi, mk cần gấp lắm lắm,...giúp mk nha....
Bài 3:
a) \(abc.1001=abcabc\)
\(abc+1000.abc=abcabc\)
\(abc+abc000=abcabc\)
\(abcabc=abcabc\left(đpcm\right)\)
b) \(1+2+3+...+2000\)
\(=\frac{\left(2000-1\right).2000}{2}\)
\(=1999000\)
Bài 1:
a) \(71-\left(33+x\right)=26\)
\(\Leftrightarrow33+x=45\)
\(\Leftrightarrow x=12\)
Vậy ...
b) \(\left(x+73\right)-26=76\)
\(\Leftrightarrow x+73=102\)
\(\Leftrightarrow x=29\)
Vậy ...
c) \(140:\left(x-8\right)=7\)
\(\Leftrightarrow x-8=20\)
\(\Leftrightarrow x=28\)
Vậy ...
d) \(6x+4x=2010\)
\(\Leftrightarrow10x=2010\)
\(\Leftrightarrow x=201\)
Vậy ...
\(a,-7624+\left(1543+7624\right)-x=25\)
\(\Leftrightarrow-7624+9167-x=25\)
\(\Leftrightarrow1543-x=25\)
\(\Leftrightarrow x=1518\)
Vậy ................
\(b,\left(27-514\right)-\left(486-73\right)+x=7\)
\(\Leftrightarrow-487-413+x=7\)
\(\Leftrightarrow-900+x=7\)
\(\Leftrightarrow x=907\)
\(c,14-12+x=10-\left|-15\right|+\left|-3\right|\)
\(\Leftrightarrow2+x=10-15+3\)
\(\Leftrightarrow2+x=-2\)
\(\Leftrightarrow x=-4\)
Vậy ....
a) - 7624 + (1543 + 7624) - x = 25
-7624 + 9167 - x = 25
1543 - x = 25
x = 1543 - 25
x = 1518
b) (27 - 514) - (486 - 73) + x = 7
(-487) - 413 + x = 7
-900 + x = 7
x = 7 - (-900)
x = 907
c) 14 - 12 + x = 10 - |-15| + |-3|
14 - 12 + x = 10 - 15 + 3
14 - 12 + x = (-5) + 3
14 - 12 + x = -2
2 + x = -2
x = (-2) - 2
x = -4
\(\left(a\right):78+58x50-58x25=78+58x\left(50-25\right)\\ =78+58x25=78+1450=1528\\ \left(b\right):326x78+327x22=326x78+326x22+1x22=326x\left(78+22\right)+22\\ =326x100+22=32600=32622\\ \left(c\right):27x39+27x63-2x27=27x\left(39+63-2\right)=27x100=2700\\ \left(d\right):48x19+48x115+134x52=48x\left(19+115\right)+134x52=48x134+134x52\\ =134x\left(48+52\right)=134x100=13400\)
a, \(78+58\times50-58\times25\)
\(=78+58\times\left(50-25\right)\)
\(=78+58\times25\)
\(=78+1450=1528\)
b, \(326\times78+327\times22\)
=\(326\times78+\left(326+1\right)\times22\)
\(=326\times78+326\times22+22\)
= \(326\times\left(78+22\right)+22\)
\(=326\times100+22\)
\(=32600+22\)
\(=32622\)
c, \(27\times39+27\times63-2\times27\)
\(=27\times\left(39+63-2\right)\)
\(=27\times100\)
\(=2700\)
d, \(48\times19+48\times115+134\times52\)
= \(48\times\left(19+115\right)+134\times52\)
\(=48\times134+134\times52\)
\(=134\times\left(48+52\right)\)
\(=134\times100\)
\(=13400\)