321:x và 15<x<320
a) ( x + 2) x 44 = 484
b) ( x + 321) : 12 = 34
c) ( x - 210) : 15 = 246
d)(205 - x) x 84 = 420
a
=> \(x+2=\dfrac{484}{44}=11\)
=> x = 11 - 2 = 9
b
=> \(x+321=34.12=408\)
=> x = 408 - 321 = 87
c
=> \(x-210=246.15=3690\)
=> x = 3690 + 210 = 3900
d
=> \(205-x=\dfrac{420}{84}=5\)
=> x = 205 - 5 = 200
a: =>x+2=11
=>x=9
b: =>x+321=408
=>x=87
c: =>x-210=3690
=>x=3900
d: =>205-x=5
=>x=200
321+{-15 + [30+(-321)]}
321+{(-15)+[30+(-321)]}=321+[(-15)+(291)]=321+(-306)=15
14-(-15)-21
321+{-15+[30+(-321)]}
(2016+432)+[168+(-2016)]
\(\text{14-(-15)-21}\)
\(=14+15-21\)
\(=29-21\)
\(=8\)
\(321+\left\{-15+\left[30+\left(-321\right)\right]\right\}\)
\(=321+\left(-15\right)+30+\left(-321\right)\)
\(=\left(321+\left(-321\right)\right)+\left(\left(-15\right)+30\right)\)
\(=0+15\)
\(=15\)
\(\text{(2016+432)+[168+(-2016)]}\)
\(=2016+432+168+\left(-2016\right)\)
\(=\left[2016+\left(-2016\right)\right]+\left(432+168\right)\)
\(=0+600\)
\(=600\)
học tốt
Tính nhanh
a . 321 + ( − 15 ) + [ 30 + ( − 321 ) ] b . ( 2018 + 432 ) + [ 168 + ( − 2018 ) ]
a, ( -2009 ) - ( 234 - 2009 )
b, ( 134 - 167 + 45 ) - ( 134 + 45 )
c, 321 + { -15 + [ 30 + ( -321 ) ]}
\(a.\left(-2009\right)-\left(234-2009\right)\\ =-2009-234+2009\\ =\left(-2009+2009\right)-234\\ =0-234\\ =-234\)
\(b.\left(134-167+45\right)-\left(134+45\right)\\ =134-167+45-134-45\\ =\left(134-134\right)+\left(45-45\right)-167\\ =0+0-167\\ =0-167\\ =-167\)
321 x 321 x 321 x 321 x 0 =
321x321x321x321x0=0
1. Tìm x:
a) /x/ + 2 = 23 . (-2)2
b) /x/ + 4 = (-3)2 + (-2)
2. Tính:
a) 5 . ( -5 - 6 )
b) 321 + { -15 + [ 30 + ( -321 )]}
c) 19 . 92 - 9 . ( -19 ) - 19
a) \(\left|x\right|+2=2^3.\left(-2\right)^2\)
\(\Leftrightarrow\)\(\left|x\right|+2=32\)
\(\Leftrightarrow\)\(\left|x\right|=30\)
\(\Leftrightarrow\)\(x=\pm30\)
Vậy...
b) \(\left|x\right|+4=\left(-3\right)^2+\left(-2\right)\)
\(\Leftrightarrow\)\(\left|x\right|+4=7\)
\(\Leftrightarrow\)\(\left|x\right|=3\)
\(\Leftrightarrow\)\(x=\pm10\)
Vậy...
b2 :
a) 5 . ( -5 - 6 )
= 5 . ( -11 )
= -55
b) 321 + { - 15 + [ 30 + ( -321 ) ] }
= 321 + { - 15 + [ - 291 ] }
= 321 + ( - 306 )
= 15
19 . 92 - 9 . ( - 19 ) - 19
= 1748 - ( -171 ) - 19
= 1919 - 19
= 1900
Tinh nhanh :
a, 321 + { 15 + [ 30 + (-321) ] }
b, ( 2016 + 432 ) + [ 168 + (-2016) ]
a)=321+15+30+(-321)
=[321+(-321)]+(15+30)
=0+45=45
b)=2016+432+168+(-2016)
=[2016+(-2016)]+(432+168)
=0+600=600
a)321+{15+[30+(-321)]}=[321+(-321)]+(15+30)=0+45=45
b)(2016+432)+[168+(-2016)]=[2016+(-2016)]+(432+168)=0+600=600
Tính nhanh
321 + { -15 + [ 30 + ( - 321)] }
( 2016 + 432 ) + ( 168 + ( - 2016)
321 + { -15 + [ 30 + (-321) ] }
= 321 + { -15 + [ 30 - 321 ] }
= 321 + { -15 + 30 - 321 }
= 321 - 15 + 30 - 321
= (321 - 321) - (15 - 30)
= 0 - (-15)
= 15
(2016 + 432) + [168 + (-2016) ]
= 2016 + 432 + [ 168 - 2016 ]
= 2016 + 432 + 168 - 2016
= (2016 - 2016) + (432 + 168)
= 0 + 600
= 600
minh khong biet dau minh chi moi lop 5 thoi
chuc ban nam moi vui ve
thank you very much