Tim x
8x+ 15=6.( x-1) + 27
1)tim x bit a)(1/2-1/3).6^x+6^x+2=6^15+6^18
b)3^x+3^x+2=2430
c)(2x-15)^5=(2x-15)^3
2) so saanh
a)2^11 va 5^35
b)2^31 va 3^21
c)2^15 va 27^5.49^8 d)21^15 va 27^5.49^8
1)tim x bit a)(1/2-1/3).6^x+6^x+2=6^15+6^18
b)3^x+3^x+2=2430
c)(2x-15)^5=(2x-15)^3
2) so saanh a)2^11 va 5^35
b)2^31 va 3^21
c)2^15 va 27^5.49^8 d)21^15 va 27^5.49^8
1.
b) \(3^x+3^{x+2}=2430\)
\(\Rightarrow3^x.1+3^x.3^2=2430\)
\(\Rightarrow3^x.\left(1+3^2\right)=2430\)
\(\Rightarrow3^x.10=2430\)
\(\Rightarrow3^x=2430:10\)
\(\Rightarrow3^x=243\)
\(\Rightarrow3^x=3^5\)
\(\Rightarrow x=5\)
Vậy \(x=5.\)
c) \(\left(2x-15\right)^5=\left(2x-15\right)^3\)
\(\Rightarrow\left(2x-15\right)^5-\left(2x-15\right)^3=0\)
\(\Rightarrow\left(2x-15\right)^3.\left[\left(2x-15\right)^2-1\right]=0\)
\(\Rightarrow\left[{}\begin{matrix}\left(2x-15\right)^3=0\\\left(2x-15\right)^2-1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}2x-15=0\\\left(2x-15\right)^2=1\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}2x=15\\2x-15=\pm1\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=15:2\\2x-15=1\\2x-15=-1\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{15}{2}\\2x=16\\2x=14\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{15}{2}\\x=8\\x=7\end{matrix}\right.\)
Vậy \(x\in\left\{\frac{15}{2};8;7\right\}.\)
Chúc bạn học tốt!
Tim X
3) -12 + (2x – 9) + x= 0
4) 11 + (15 - x) = 1
5) 4 - (27 - 3) = x - (13 - 4)
6) 8 - (x - 10) = 23 - (- 4 +12)
7) 105 – 5(10 – 5x) = -20
8) (x -1)(8-2x)(3x+123) = 0
9) (x2 - 25)(x+ 10) = 0
10) x(x2+5) =
3) \(-12+2x-9+x=0\\ -21+3x=0\\ 3x=21\\ x=7\)
4)
\(11+\left(15-x\right)=1\)
\(15-x=1-11\)
\(15-x=-10\)
\(x=15-\left(-10\right)\)
\(x=25\)
5)
\(4-\left(27-3\right)=x-\left(13-4\right)\)
\(4-24=x-9\)
\(x-9=-20\)
\(x=-20+9\)
\(x=-11\)
\(3.-12+\left(2x-9\right)+x=0.\)
\(\Leftrightarrow-12+2x-9+x=0.\Leftrightarrow3x=21.\Leftrightarrow x=7.\)
Vậy \(x=7.\)
\(4.11+\left(15-x\right)=1.\Leftrightarrow11+15-x=1.\Leftrightarrow26-x=1.\Leftrightarrow x=25.\)
Vậy \(x=25.\)
\(5.4-\left(27-3\right)=x-\left(13-4\right).\Leftrightarrow4-24=x-9.\Leftrightarrow-20=x-9.\Leftrightarrow x=-11.\)
Vậy \(x=-11.\)
\(6.8-\left(x-10\right)=23-\left(-4+12\right).\Leftrightarrow8-x+10=23-8.\Leftrightarrow18-x=15.\Leftrightarrow x=3.\)
Vậy \(x=3.\)
\(7.105-5\left(10-5x\right)=-20.\Leftrightarrow105-50+25x=-20.\Leftrightarrow25x=-75.\Leftrightarrow x=-3.\)
Vậy \(x=-3.\)
\(8.\left(x-1\right)\left(8-2x\right)\left(3x+123\right)=0.\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=0.\\8-2x=0.\\3x+123=0.\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1.\\x=4.\\x=-41.\end{matrix}\right.\)
Vậy \(x\in\left\{1;4;-41\right\}.\)
\(9.\left(x^2-25\right)\left(x+10\right)=0.\)
\(\Leftrightarrow\left(x-5\right)\left(x+5\right)\left(x+10\right)=0.\)
\(\Leftrightarrow\left[{}\begin{matrix}x-5=0.\\x+5=0.\\x+10=0.\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5.\\x=-5.\\x=-10.\end{matrix}\right.\)
Vậy \(x\in\left\{5;-5;-10\right\}.\)
\(10.x\left(x^2+5\right)=0.\Leftrightarrow x=0.\)
cau 1.tim x
a)15-|x-4|=6
b)-30+|25-x|=-1
c)x-(12-25)=-8
d) (x-29)-(17-38)=-9
cau 2.tim so nguyen x
a,22-(-x)=12
b,(x+5)+(x-9)=x+2
c,(27-x)+(15+x)=x-24
27.(-16)+(-16).74+16
15+(-12)-(-18)-24-(-6)
2/tim x
4x-15= -75-x
3/tim x thuoc z sao cho 12 chia het cho (x-3)
cac bn giup mk nhe
Bài 1 bạn tự là nhé dễ lắm :))
Bài 2 :
Ta có :
\(4x-15=-75-x\)
\(\Leftrightarrow\)\(4x+x=-75+15\)
\(\Leftrightarrow\)\(5x=-60\)
\(\Leftrightarrow\)\(x=\frac{-60}{5}\)
\(\Leftrightarrow\)\(x=-12\)
Bài 3 :
Ta có :
\(12⋮\left(x-3\right)\)\(\Rightarrow\)\(\left(x-3\right)\inƯ\left(12\right)\)
Mà \(Ư\left(12\right)=\left\{1;-1;2;-2;3;-3;4;-4;6;-6;12;-12\right\}\)
Suy ra : ( lập bảng )
\(x-3\) | \(1\) | \(-1\) | \(2\) | \(-2\) | \(3\) | \(-3\) | \(4\) | \(-4\) | \(6\) | \(-6\) | \(12\) | \(-12\) |
\(x\) | \(4\) | \(2\) | \(5\) | \(1\) | \(6\) | \(0\) | \(7\) | \(-1\) | \(9\) | \(-3\) | \(15\) | \(-9\) |
Vậy \(x\in\left\{4;2;5;1;6;0;7;-1;9;-3;15;-9\right\}\)
Chúc bạn học tốt
bai 1:tim x
a,(27.x+6):3-11=9
b,(15-6x).35=36
c,(2x-6).47=49
giup minh voi !!!!!!!!!
\(a,\left(27x+6\right):3-11=9\)
\(\Rightarrow\left(27x-6\right):3=20\)\(\Rightarrow27x-6=60\)\(\Rightarrow27x=66\)\(\Rightarrow x=\frac{22}{9}\)
\(b,\left(15-6x\right).3^5=3^6\)
\(\Rightarrow15-6x=3\)\(\Rightarrow6x=12\)\(\Rightarrow x=2\)
\(c,\left(2x-6\right).4^7=4^9\)
\(\Rightarrow2x-6=16\)\(\Rightarrow2x=22\)\(\Rightarrow x=11\)
Bài 1: Tìm x
a,(27.x+6):3-11=9
﴾ 27x + 6﴿ : 3 ‐ 11 = 9
﴾ 27x + 6﴿ : 3 = 20
27x + 6 = 60
27x = 54
x = 54 : 27
x = 2
Vậy x = 2
b,( 15-6x ) . 35=36
( 15 - 6x ) = 36 : 35
15 - 6x = 3
6x = 15 - 3
6x = 12
x = 12 : 6
x = 2
Vậy x = 2
c,( 2x-6 ) . 47=49
2x - 6 = 49 : 47
2x - 6 = 16
2x = 16 + 6
2x = 22
x = 22 : 2
x = 11
Vậy x = 11
tim x thoa man 9-(27-2x)=-/-27/-15
9-(27-2x)=-|-27|-15
9-(27-2x)=-42
27-2x = 51
2x = 27 - 51
2x = -24
x = -24 : 2
x = -12
tim xez:a,x+1/37=27/x+1 b,x/5=6/x+1
1. Tinh
39 x 148 + 15 x (-74) -48 x 39 + (-15) x 26
(-78) : 6 + (-345) : (-15)
(-3) x { 48 - [ 27 + 4 x (-3)2 ] }
2. Tim x
( x - 2)2 + 16 = 32
( x + 3 )2 + 25 = -56
Bài tinh thi các bạn tinh nhanh hộ minh