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a: =6/35x39/54=13/105
b: \(=\dfrac{-5}{7}\left(\dfrac{2}{11}+\dfrac{9}{11}\right)+\dfrac{12}{7}=\dfrac{-5}{7}+\dfrac{12}{7}=1\)
1 .
[ 6 + ( 1/2 ) 3 - /-0,5/ ] : 3/12
= [ 6 + 1/8 - ( -5/10 ) ] . 12/3
= [ 6 + 1/8 + 5/10 ] .4
= [ 6 + 1/8 + 1/2 ] .4
= [ 48/8 + 1/8 + 4/8 ] .4
= 53/8 . 4
= 53 . 1/2
= 53/2
2.
1/3 + 5/4 : (-35/16)
= 1/3 + 5/4 . ( 16/-35 )
= 1/3 + 1 . 4/4 . (-7 )
= 1/3 + 4/28
= 1/3 + 1/7
= 7/21 + 3/21
= 10/21
3 .
11 3/13 - ( 2 4/7 + 5 3/13 )
= 11 3/13 - 2 4/7 - 5 3/13
= { [ ( 11 - 5 ) . ( 3/13 - 3/13 ) } - 2 4/7
= ( 6 . 0 ) - 2 4/7
= 0 - 18/7
= 18/7
4 .
1 3/7 + (-1/3 + 2 4/7 )
= 1 3/7 + ( -1 )/3 + 2 4/7
={ [ ( 1 + 2 ) . ( 3/7 + 4/7 ) } + ( -1 )/3
= ( 3 . 1 ) + ( -1 )/3
= 3 + ( -1 )/3
= 9/3 + ( -1 )/3
= 8/3
5 .
( 6 4/9 + 3 7/11 ) - 4 4/9
= 6 4/9 + 3 7/11 - 4 4/9
= { ( 6 - 4 ) . ( 4/9 - 4/9 ) } + 3 7/11
= ( 2 . 0 ) + 3 7/11
= 0 + 40/11
= 40/11
Nếu đúng thì k cho mình nha !
Bài làm
1.
11 3/13 - ( 2 4/7 + 5 3/13 )
= 11 3/13 - 2 4/7 - 5 3/13
= ( 11 3/13 - 5 3/13 ) - 2 4/7
= { (11 - 5 ) . ( 3/13 - 3/13 ) } - 2 4/7
= ( 6 . 0 ) - 2 4/7
= 0 - 2 4/7
= 2 4/7
= 18/7
2 .
19 5/8 : 7/12 + ( -15 1/4) : 7/12
= { 19 5/8 + ( -15 1/4 ) } : 7/12
= [ { 19 + ( - 15) } . ( 5/8 + 1/4 ) ] : 7/12
= { 4 . ( 5/8 + 2/8 ) } : 7/12
= ( 4 . 7/8 ) : 7/12
= 1.7/2 : 7/12
= 7/2 : 7/12
= 7/2 . 12/7
= 1.1/6.1
= 1/6
3 .
2/5 . 1/3 - 2 2/15 : 1/5 + 3/5 . 1/3
= 1/3 . ( 2/5 + 3/5 ) - 2 2/15 : 1/5
= 1/3 . 5/5 - 32/15 . 5/1
= 1/3 . 1 - 32.1/3.1
= 1/3 - 32/3
= -31/3
4 .
( 3 1/3 + 2,5 ) : ( 3 1/6 - 4 1/5 ) - 11/31
= ( 10/3 + 25/10 ) : { ( 3 - 4 ) . ( 1/6 - 1/5 ) - 11/31
= ( 10/3 + 5/2 ) : { (-1) . ( 5/30 - 6/30 ) } - 11/31
= ( 20/6 + 15/6 ) : { (-1) . (-1)/30 } - 11/31
= 35/6 : 1/30 - 11/31
= 35/6 . 30/1 - 11/31
= 35.5/1.1 - 11/31
= 175 - 11/31
= 5425/31 - 11/31
= 5414/31
5.
75% - 1 1/5 + 0,5 : 5/12 - (-1/2)2
= 75/100 - 6/5 + 5/12 - 1/4
= 3/4 - 6/5 + 5/12 - 1/4
= ( 3/4 - 1/4 ) + ( 5/12 - 6/5 )
= 2/4 + ( 25/60 - 30/60 )
= 1/2 + (-5)/60
= 1/2 + (-1)/12
= 6/12 + (-1)/12
= 5/12
Đúng thì k cho mình nha !
1)
11 3/13 - ( 2 4/7 + 5 3/13 )
= 11 3/13 - 2 4/7 - 5 3/13
= ( 11 3/13 - 5 3/13 ) - 2 4/7
= { (11 - 5 ) . ( 3/13 - 3/13 ) } - 2 4/7
= ( 6 . 0 ) - 2 4/7
= 0 - 2 4/7
= 2 4/7
= 18/7
2 )
19 5/8 : 7/12 + ( -15 1/4) : 7/12
= { 19 5/8 + ( -15 1/4 ) } : 7/12
= [ { 19 + ( - 15) } . ( 5/8 + 1/4 ) ] : 7/12
= { 4 . ( 5/8 + 2/8 ) } : 7/12
= ( 4 . 7/8 ) : 7/12
= 1.7/2 : 7/12
= 7/2 : 7/12
= 7/2 . 12/7
= 1.1/6.1
= 1/6
3 )
2/5 . 1/3 - 2 2/15 : 1/5 + 3/5 . 1/3
= 1/3 . ( 2/5 + 3/5 ) - 2 2/15 : 1/5
= 1/3 . 5/5 - 32/15 . 5/1
= 1/3 . 1 - 32.1/3.1
= 1/3 - 32/3
= -31/3
4 )
( 3 1/3 + 2,5 ) : ( 3 1/6 - 4 1/5 ) - 11/31
= ( 10/3 + 25/10 ) : { ( 3 - 4 ) . ( 1/6 - 1/5 ) - 11/31
= ( 10/3 + 5/2 ) : { (-1) . ( 5/30 - 6/30 ) } - 11/31
= ( 20/6 + 15/6 ) : { (-1) . (-1)/30 } - 11/31
= 35/6 : 1/30 - 11/31
= 35/6 . 30/1 - 11/31
= 35.5/1.1 - 11/31
= 175 - 11/31
= 5425/31 - 11/31
= 5414/31
5)
75% - 1 1/5 + 0,5 : 5/12 - (-1/2)2
= 75/100 - 6/5 + 5/12 - 1/4
= 3/4 - 6/5 + 5/12 - 1/4
= ( 3/4 - 1/4 ) + ( 5/12 - 6/5 )
= 2/4 + ( 25/60 - 30/60 )
= 1/2 + (-5)/60
= 1/2 + (-1)/12
= 6/12 + (-1)/12
= 5/12
a; - \(\dfrac{10}{13}\) + \(\dfrac{5}{17}\) - \(\dfrac{3}{13}\) + \(\dfrac{12}{17}\) - \(\dfrac{11}{20}\)
= - (\(\dfrac{10}{13}\) + \(\dfrac{3}{13}\)) + (\(\dfrac{5}{17}\) + \(\dfrac{12}{17}\)) - \(\dfrac{11}{20}\)
= - 1 + 1 - \(\dfrac{11}{20}\)
= 0 - \(\dfrac{11}{20}\)
= - \(\dfrac{11}{20}\)
b; \(\dfrac{3}{4}\) + \(\dfrac{-5}{6}\) - \(\dfrac{11}{-12}\)
= \(\dfrac{9}{12}\) - \(\dfrac{10}{12}\) + \(\dfrac{11}{12}\)
= \(\dfrac{10}{12}\)
= \(\dfrac{5}{6}\)
c; [13.\(\dfrac{4}{9}\) + 2.\(\dfrac{1}{9}\)] - 3.\(\dfrac{4}{9}\)
= [\(\dfrac{52}{9}\) + \(\dfrac{2}{9}\)] - \(\dfrac{4}{3}\)
= \(\dfrac{54}{9}\) - \(\dfrac{4}{3}\)
= \(\dfrac{14}{3}\)
1.
a) (1/3+3/4-13/12):(12/23+123/234+1234/2345)
=0:(12/23+123/234+1234/2345)
=0
b) |x+1|=5
⇒x+1=5 hoặc x+1=-5
x=4 hoặc x=-6
2.
Giải
a) Số h/s khá của lớp 6A là:
40.60%=24 (h/s)
Số h/s tb của lớp 6A là:
24.1/6=4 (h/s)
Số h/s giỏi của lớp 6A là:
40-(24+4)=12 (h/s)
b) Tỉ số % của h/s tb với h/s cả lớp là:
4/40.100%=10%