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Ư(6)={1;2;3;6}
Voi x +3=1=≫x=1-3=-2
Voi x+3=2=≫x=2-3=-1
Voi x+3=3=≫x=3-3=0
Voi x+3=6=≫x=6-3=3
Vi 10 la boi cua 2x+5=≫2x+5 la uoc cua 10=≫ Ư(10={1;2;5;10}
Voi 2x+5=1=≫2x=1-5=-4=≫x=4÷2=2
Voi 2x+5=2=≫ 2x=2-5=-3=≫x=-3÷2= -1,5
Voi 2x+5=5=≫5-5=0=≫x=0÷2=0
Voi 2x+5=10=≫2x=10-5=5=≫x=5÷2=2,5
1) \(x-36:18=12\)
\(\Leftrightarrow x-2=12\)
\(\Rightarrow x=14\)
2) \(x-38:12=12\)
\(\Leftrightarrow x-\frac{19}{6}=12\)
\(\Rightarrow x=\frac{91}{6}\)
3) \(\left(25+x\right)-20:4=35\)
\(\Leftrightarrow25+x-5=35\)
\(\Leftrightarrow x=15\)
4) \(720:\left[41-\left(2x-5\right)\right]+8=48\)
\(\Leftrightarrow41-2x+5=18\)
\(\Leftrightarrow2x=28\)
\(\Rightarrow x=14\)
5) \(5x-x+15=223\)
\(\Leftrightarrow4x=208\)
\(\Rightarrow x=52\)
6) \(7x-55=2x\)
\(\Leftrightarrow5x=55\)
\(\Rightarrow x=11\)
7) \(\left(x-10\right).11=0\)
\(\Leftrightarrow x-10=0\)
\(\Rightarrow x=10\)
a)
x= 43
b) 2X-12=8
2X =8+12
2X=20
X=20:2
x =10
c)45:(3X-17)=32
45 : (3X-17)=9
3X-17=45:9
3X-17=5
3X=5+17
3X=22
x=22:3
x= 7,33
d)(2X-8)x2=24
( 2X-8)x2 =16
2X-8 =16:2
2X-8 =8
2X =8+8
2X =16
x =16:2
X =8
Đúng thì tk nếu sai thì thôi
Làm ẩu ^^
\(A=3x-x^2\)
\(=-\left(x^2-2.x.\frac{3}{2}+\left(\frac{3}{2}\right)^2-\frac{9}{4}\right)\)
\(=-\left(\left(x-\frac{3}{2}\right)^2-\frac{9}{4}\right)\)
\(=\frac{9}{4}-\left(x-\frac{3}{2}\right)^2\ge\frac{9}{4}\)
Min A = \(\frac{9}{4}\)khi \(x-\frac{3}{2}=0=>x=\frac{3}{2}\)
\(B=25+2x-x^2\)
\(=-\left(x^2-2x+1-26\right)\)
\(=-\left(\left(x-1\right)^2-26\right)\)
\(=26-\left(x-1\right)^2\ge26\)
Min A = 26 khi \(x-1=0=>x=1\)
\(C=x^2-5x+19\)
\(=x^2-2.x.\frac{5}{2}+\left(\frac{5}{2}\right)^2+\frac{51}{4}\)
\(=\left(x+\frac{5}{2}\right)^2+\frac{51}{4}\ge\frac{51}{4}\)
Min C = \(\frac{51}{4}\)khi \(x+\frac{5}{2}=0=>x=\frac{-5}{2}\)
@@@ nha các bạn . Thanks
\(x^4\cdot x^7\cdot...\cdot x^{100}\)
\(=x^{4+7+...+100}\)
\(=x^{52\cdot33}=x^{1716}\)
\(x^1\cdot x^2\cdot x^3\cdot...\cdot x^{2006}\)
Ta có : \(x^1\cdot x^2=x^{1+2}=x^3\)
Tương tự : \(x^1\cdot x^2\cdot x^3=x^{1+2+3}=x^6\)
Áp dụng vào bài toán :
\(x^1\cdot x^2\cdot x^3\cdot...\cdot x^{2006}=x^{1+2+3+...+2006}\)
\(\Rightarrow x^{1+2+3+...+2006}=x^{2013021}\)
a) \(\left(5x+3^4\right).6^8=6^9.3^4\)
\(=>6x+3^4=3^4.6^9:6^8\)
\(=>6x+3^4=3^4.6\)
\(=>6x=6.3^4-3^4\)
\(=>6x=0\)
\(=>x=0:6\)
\(=>x=0\)
a/(5x + 34).68=69.34
(5x + 34) = 69:68.34
5x + 81 = 6.81
5x = 6.81 - 81
5x = 486 - 81
5x = 425
x = 425:5
x = 85
b/92 - 2x = 2.42- 3.4 + 120:15
92 - 2x = 2.16 - 12 + 8
92 - 2x = 32 - 12 + 8
92 - 2x = 28
2x = 92 - 28
2x = 64
x = 64:2
x = 32
c/53.(3x + 2) : 13 = 103: (135:134)
125.(3x + 2) : 13 = 1000:13
125.(3x+2) = 1000:13.13
125.(3x+2) = 1000
3x + 2 = 1000:125
3x + 2 = 8
3x = 8 - 2
3x = 6
x = 6:3
x = 2
Bạn nhớ tick cho mình nhé!
a) -12.(x - 5) + 7(3 - x) = 5
=> -12x + 60 + 21 - 7x = 5
=> -19x + 81 = 5
=> -19x = 5 - 81
=> -19x = -76
=> x = -76 : (-19)
=> x = 4
b) (x + 1) + (x + 2) + (x + 3) + ... + (x + 20) = 250
=> (x + x + x + ... + x) + (1 + 2 + 3 + ... + 20) = 250
=> 20x + 210 = 250
=> 20x = 250 - 210
=> 20x = 40
= > x = 40 : 20
=> x = 2
\(-12\left(x-5\right)+7\left(3-x\right)=5\)
\(\Leftrightarrow-12x+60+21-7x=5\)
\(\Leftrightarrow-19x+81=5\)
\(\Leftrightarrow81-5=19x\)
\(\Leftrightarrow19x=76\)
\(\Leftrightarrow x=4\)
131 . x - 942 = 2^7 . 2^3
131 . x - 942 = 2^10
131 . x - 942 = 1024
131 . x = 1024 + 942
131 . x = 1966
x = 1966 : 131
x \(\approx15\)
b ) [ ( x + 32 ) - 17 ] . 2 = 42
[ ( x + 32 ) - 17 ] = 42 : 2
( x + 32 ) - 17 = 21
x + 32 = 21 + 17
x + 32 = 38
x = 38 - 32
x = 6
5x + x= 150: 2+ 3
6x = 150 : 2 + 3
6x = 75 + 3
6x = 78
x = 78 : 6
x = 13
b,
6x + x = 25 + 3
7x = 28
x = 28 : 7
x = 4
c,
5x + x= 39 - 9
6x = 30
6x = 30 : 6
x = 5
d,
7x - x= 25+ 3 . 4 -1
6x = 25+ 3 . 4 -1
6x = 25 + 12 - 1
6x = 37 - 1
6x = 36
x = 36 : 6
x = 6