5*2
15+15
16+16
17+17
Làm tính chia:
a) 17 3 : ( - 17 ) - 2 ; b) − 7 6 8 : 7 − 6 4 ;
c) ( 3 z ) 3 : 4 z 2 ; d) 15 16 ( − x 5 ) 3 : 16 5 x 6 .
16) M = (-32 + 215) - (-30 + 215)
17) N = -5 + (-37 - 45 + 151) - (-37 + 151)
Giúp mk với!!!!!☹
16) M = (-32 + 215) - (-30 + 215)
= -32 + 215 + 30 - 215
= (215 - 215) + (30 - 32)
= 0 - 2 = -2
17) N = -5 + (-37 - 45 + 151) - (-37 + 151)
= -5 - 37 - 45 + 151 + 37 - 151
= (151 - 151) - (5+45) + (37 - 37)
= 0 - 50 + 0 = -50
so sanh hai phan so A=2/5+2/15+4/215-422/2015:17/5+27/5+239/215-4.517/2015 va B=2/84+2/112+1/72+4/360
bài 2
1)-5/8*15/4
2) -15/17*25/-34
3) -12*8/3
4)-15/14*20/-21
5)-48*(-24/5)
1: \(=\dfrac{-5}{8}\cdot\dfrac{15}{4}=-\dfrac{75}{32}\)
2: \(=\dfrac{15}{17}\cdot\dfrac{25}{34}=\dfrac{375}{578}\)
3: \(=-12\cdot\dfrac{8}{3}=-4\cdot8=-32\)
4: \(=\dfrac{15}{14}\cdot\dfrac{20}{21}=\dfrac{50}{49}\)
5: \(=48\cdot\dfrac{24}{5}=230.4\)
\(a,-215-358+215+\left(-42\right)\\ =\left(-215+215\right)+\left(-358-42\right)\\ =0-400\\ =-400\\ b,13\cdot\left(23+22\right)-3\cdot\left(17+28\right)\\ =13\cdot45-3\cdot45\\ =45\cdot\left(13-3\right)\\ =45\cdot10\\ =450\)
Tính tổng sau bằng cách hợp lí nhất
a) − 7 31 + 24 19 + 1 15 + 7 31 + − 5 19
b) 15 16 + 13 33 + 1 11 + 7 33 + − 15 16 + 20 66
a)
− 7 31 + 24 19 + 1 15 + 7 31 + − 5 19 = − 7 31 + 7 31 + 24 19 + − 5 19 + 1 15 = 1 + 1 15 = 16 15
b)
15 16 + 13 33 + 1 11 + 7 33 + − 15 16 + 20 66 = 15 16 + 13 33 + 1 11 + 7 33 + − 15 16 + 20 66 = 15 16 + − 15 16 + 13 33 + 7 33 + 1 11 + 20 66 = 20 33 + 13 33 = 1
Tính giá trị của biểu thức.
a) 8 103 × 5 – 4 135 b) 24 360 : 8+ 9 600
c) 839 + 6 215 x 4 d) 17 286 - 45 234 : 9
a)
8 103 × 5 – 4 135
= 40 515 – 4 135
= 36 380
b)
24 360 : 8+ 9 600
= 3045 + 9 600
= 12 645
c)
839 + 6 215 × 4
= 839 + 24 860
= 25 699
d)
17 286 – 45 234 : 9
= 17 286 – 5 026
= 12 260
13) x+ \(\sqrt{x}\) - 6
14) x - 2\(\sqrt{x}\) - 5
15) x + 2\(\sqrt{x}\) -15
16) 2x - 5\(\sqrt{x}\) + 3
13: \(x+\sqrt{x}-6=\left(\sqrt{x}+3\right)\left(\sqrt{x}-2\right)\)
15: \(x+2\sqrt{x}-15=\left(\sqrt{x}+5\right)\left(\sqrt{x}-3\right)\)
16: \(2x-5\sqrt{x}+3=\left(\sqrt{x}-1\right)\left(2\sqrt{x}-3\right)\)
12+17-4256+215-173=???
12 + 17 - 4256 + 215 - 173 = 19 - 4256 + 215 - 173
= -4237 + 215 - 173
= -4022 - 173
= -4195
Bài1 :Tìm x:
( 6 : 3/5 - 17/16 . 6/7 / 21/5 . 10/11 + 57/11 - (3/20 + 1/2 - 1/15) . 12/49 / 10/3 + 2/9 ) . x = 215/96
Ai nhanh mk K ạ.
\(\left(\dfrac{6:\dfrac{3}{5}-\dfrac{17}{16}.\dfrac{6}{7}}{\dfrac{21}{5}.\dfrac{10}{11}+\dfrac{57}{11}}-\dfrac{\left(\dfrac{3}{20}+\dfrac{1}{2}-\dfrac{1}{15}\right).\dfrac{12}{49}}{\dfrac{10}{3}+\dfrac{2}{9}}\right).x=\dfrac{215}{96}\)
\(\Rightarrow\left(\dfrac{\dfrac{509}{56}}{9}-\dfrac{\dfrac{7}{12}.\dfrac{12}{49}}{\dfrac{32}{9}}\right).x=\dfrac{215}{96}\)
\(\Rightarrow\left(\dfrac{509}{504}-\dfrac{\dfrac{1}{7}}{\dfrac{32}{9}}\right).x=\dfrac{215}{96}\)
\(\Rightarrow\left(\dfrac{509}{504}-\dfrac{9}{224}\right).x=\dfrac{215}{96}\)
\(\Rightarrow\dfrac{1955}{2016}.x=\dfrac{215}{96}\)
\(\Rightarrow x=\dfrac{215}{96}:\dfrac{1955}{2016}\)
\(\Rightarrow x=\dfrac{903}{391}\)
`[ 6 : 3/5 - 17/16 . 6/7 : 21/5 . 10/11 + 57/11 - (3/20 + 1/2 - 1/15) . 12/49 : 10/3 + 2/9 ] . x = 215/96`
`=>[ 6 . 5/3 - 17/16 . 6/7 . 5/21 . 10/11 + 57/11 - (3/20 + 1/2 - 1/15) . 12/49 . 3/10 + 2/9 ] . x = 215/96`
`=>[10- 51/56 . 6/7 . 5/21 . 10/11 + 57/11 - (3/20 + 1/2 - 1/15) . 12/49 . 3/10 + 2/9 ] . x = 215/96`
`=> [10- 153/196 . 5/21 . 10/11 + 57/11 - (3/20 + 1/2 - 1/15) . 12/49 . 3/10 + 2/9 ] . x = 215/96`
`=> [10- 255/1372 . 10/11 + 57/11 - (3/20 + 1/2 - 1/15) . 12/49 . 3/10 + 2/9 ] . x = 215/96`
`=> [10- 1275/7546 + 57/11 - (3/20 + 1/2 - 1/15) . 12/49 . 3/10 + 2/9 ] . x = 215/96`
`=> (10- 1275/7546 + 57/11 - 7/12. 12/49 . 3/10 + 2/9 ) . x = 215/96`
`=> ( 10- 1275/7546 + 57/11 -343/600 . 3/10 + 2/9 ) . x = 215/96`
`=> ( 10- 1275/7546 + 57/11 -343/2000 + 2/9 ) . x = 215/96`
`=>15,06357671 . x= 215/96`
`=> x= 215/96: 15,06357671`
`=>x= 0,1486754027`
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