(296:(78-(579-30.7):9)).18
36.72-36.67
{296:[78-(579-30.7):9]}.18
3x-5=16
42-2.(32-2x+1)=10
GIÚP MÌNH,HELP MY
36.72-36.67=36.(72-67)=36.5=180 {296:[78-(579-30.7):9]}.18={296:[78-369:9]}.18=296:37.18=8.18=144 3x-5=16=3x-5=16+5.3x+5=21.x = 21:3.x = 7 vay x =7 phan kia minh ko bie,bn thong cam cho minh nha.minh can nhgieng cuu
\(36\cdot72-36\cdot67\)
\(=36\left(72-67\right)\)
\(=36\cdot5\)
\(=180\)
tính va tim x:
a,36.72-36.67
b,{296:[78-(579-30.7):9]}.18
c,3x-5=16
d,42-2.(32-2x+1)=10
GIUP MINH
Điền vào chỗ trống ( > <=)
1201 … 999 24 601 … 2461
43 658 … 43 690 138 579 … 138 701
5178 … 5100 + 78 520 000 … 419 999
1201 > 999 24 601 > 2461
43 658 <43 690 138 579 < 138 701
5178 = 5100 + 78 520 000 > 419 999
Tìm x
9x-1 = 9
( 6x - 18 ) : 3 + 25 . 2 = 78
\(9^{x-1}=9\)
\(9^{x-1}=9^1\)
\(x-1=1\)
\(x=1+1\)
\(x=2\)
\(\frac{6x-18}{3}+25\times2=78\)
\(\frac{6\left(x-3\right)}{3}+50=78\)
\(2\left(x-3\right)=78-50\)
\(2x-6=28\)
\(2x=28+6\)
\(2x=34\)
\(x=\frac{34}{2}\)
\(x=17\)
a) \(9^{x-1}=9\)
\(\Rightarrow x-1=1\)
\(\Rightarrow x=2\)
Vậy \(x=2\)
b) \(\left(6x-18\right):3+25.2=78\)
\(\Rightarrow3\left(2x-6\right):3+50=78\)
\(\Rightarrow2x-6=38\)
\(\Rightarrow2x=44\)
\(\Rightarrow x=22\)
Vậy \(x=22\)
chứng minh rằng : 3^21 - 3^18 chia hết 78 81^7 - 27^9 - 9^13 chia hết cho 45
a)
\(3^{21}-3^{18}\\ =3^{17}.\left(3^4-3\right)\\ =3^{17}.\left(81-3\right)\\ =3^{17}.78\)
Vì \(3^{17}.78⋮78\) nên \(3^{21}-3^{18}⋮78\) (đpcm)
Vậy...
b)
\(81^7-27^9-9^{13}\\
=\left(3^4\right)^7-\left(3^3\right)^9-\left(3^2\right)^{13}\\
=3^{28}-3^{27}-3^{26}\\
=3^{24}.\left(3^4-3^3-3^2\right)\\
=3^{24}.\left(81-27-9\right)\\
=3^{24}.45\)
Vì \(3^{24}.45⋮45\) nên \(81^7-27^9-9^{13}⋮45\) (đpcm)
Vậy...
Tính nhanh nếu có thể
a) 3 . 5 mũ 2 - 64 : 2 mũ 3
b) 53 . 18 + 2 . 9 . 78 - 18 . 40
c) 78 : { 390 : [ 410 - ( 340 + 15 . 4 ) ] } +2019 mũ 0
a)3.52-64:23
=3.25-64:8
=75-8
=67
b)53.18+2.9.78-18.40
=18.(53+2.9.78-40)
=18..(53+1404-40)
=18.1417
=25506
c)78:{390:[410-(340+15.4)]}+20190
=78:{390:[410-(340+60)]}+1
=78:{390:[410-400]}+1
=78:{390:10}+1
=78:39+1
=2+1
=3
Cho mk 1 tk nha
b, 53.18+2.9.78-18.40
=53.18+18.78-18.40
=18.(53+78-40)
=18.91
=1638
Phân số 54/78 được rút gọn thành phân số tối giản là:
A.27/39 B.9/13 C.18/26 D.13/9
Tính hợp lí: | a) 5. 11. 18 + 9. 31. 10 + 4. 29. 45;b) 37. 39 + 78. 14 + 13. 85 + 52. 55. |
a: \(5\cdot11\cdot18+9\cdot31\cdot10+4\cdot29\cdot45\)
\(=11\cdot\left(5\cdot18\right)+31\cdot\left(9\cdot10\right)+29\cdot2\cdot\left(2\cdot45\right)\)
\(=90\left(11+31+29\cdot2\right)\)
\(=90\cdot100=9000\)
b: \(37\cdot39+78\cdot14+13\cdot85+52\cdot55\)
\(=37\cdot39+39\cdot2\cdot14+13\cdot85+13\cdot4\cdot55\)
\(=39\left(37+2\cdot14\right)+13\cdot\left(85+4\cdot55\right)\)
\(=39\cdot65+13\cdot305\)
\(=13\left(65\cdot3+305\right)=13\cdot500=6500\)
a)
5.11.18+9.31.10+4.29.455.11.18+9.31.10+4.29.45
=90.11+90.31+2.29.90=90.11+90.31+2.29.90
=90.(11+31+2.29)=90.(11+31+2.29)
=90.100=9000
b)
37.39+78.14+13.85+52.5537.39+78.14+13.85+52.55
=37.39+39.2.14+13.5.17+13.4.5.11=37.39+39.2.14+13.5.17+13.4.5.11
=39.(37+2.14)+65.17+65.44=39.(37+2.14)+65.17+65.44
=39.65+65.(17+44)=39.65+65.(17+44)
=39.65+65.61=39.65+65.61
=65.(39+61)=65.(39+61)
=65.100=6500
a)
5.11.18+9.31.10+4.29.45
=90.11+90.31+2.29.90
=90.(11+31+2.29)
=90.100
=9000
b)
37.39+78.14+13.85+52.55
=37.39+39.2.14+13.5.17+13.4.5.11
=39.(37+2.14)+65.17+65.44
=39.65+65.(17+44)
=39.65+65.61
=65.(39+61)
=65.100
=6500
tìm số tận cùng
7325, 769, 25413, 3795, 2345, 2346, 2347, 5795, 5796, 5797