timf x biet x^13=27.x^10
timf x biet 1+2+3+...+ x =55
côn thức[ số đầu + số cuối ] . các số hạng / 2 = kết quả
[1+x].b/2=55
=55.2=110
=[1+10].10/2=55
=x=10
tớ chỉ có thể giải thích thế này thôi nên thứ lỗi
\(3^{x+1}+2x\cdot3^x-18x-27=0\)timf x
<=> 3x(2x+3)-9(2x+3)=0
<=> (2x+3)(3x-9)=0
<=> 2x+3=0 => x=-3/2
Và: 3x-9=0 => 3x=9=32 => x=2
Đs: x=-3/2 và x=2
timf x,y thuoc Z biet \(xy^2+2xy-4y+x=0\)
tim so nguyen x biet 4-(27-30) = x (13-4)
timf x \(\dfrac{9}{17}x+15\dfrac{13}{17}x-20\dfrac{5}{17}x=16\)
9/17.x+268/17.x-345/17.x=16
(9/17+268/17-345/17).x=16
-4.x=16
x=16:-4
x=-4
\(\dfrac{9}{17}x+15\dfrac{13}{17}x-20\dfrac{5}{17}x=16\)
\(\left(\dfrac{9}{17}+15\dfrac{13}{17}-20\dfrac{5}{17}\right)x=16\)
\(\left(\dfrac{9}{17}+\dfrac{268}{17}-\dfrac{345}{17}\right)x=16\)
\(x=16:\left(\dfrac{9}{17}+\dfrac{268}{17}-\dfrac{345}{17}\right)\)
\(x=-4\)
`(9/17+268/17-345/17)x=16`
\(⇒ ( − 4 ) x = 16\)
\(⇒ x = 16 : ( − 4 ) \)
\(⇒ x = − 4\)
CMR
a, 10^+10^8+10^7 chia het cho 222
b, 81^7-27^9-9^13 chia het cho 45
tim x thuoc Q biet
a,{x+1} {x-2} < 0
b, {x-2} {x + 0,5} nhỏ hơn 0
timf giá trị của x khi x3+3x2+3x+1=27
\(\Leftrightarrow x+1=3\)
hay x=2
tim x biet (x+2)/10^10+(x+2)/11^11=(x+2)/12^12+(x+2)/13^13
=>
\(\frac{x+2}{10^{10}}+\frac{x+2}{11^{11}}-\frac{x+2}{12^{12}}-\frac{x+2}{13^{13}}=0\)
=>\(\left(x+2\right).\left(\frac{1}{10^{10}}+\frac{1}{11^{11}}-\frac{1}{12^{12}}-\frac{1}{13^{13}}=0\right)\)
vì \(\frac{1}{10^{10}}>\frac{1}{11^{11}}>\frac{1}{12^{12}}>\frac{1}{13^{13}}=>\frac{1}{10^{10}}+\frac{1}{11^{11}}-\frac{1}{12^{12}}-\frac{1}{13^{13}}\ne0\)
=>x+2=0
=>x=-2
tick nhé
\(\frac{x+2}{10^{10}}+\frac{x+2}{11^{11}}=\frac{x+2}{12^{12}}+\frac{x+2}{13^{13}}\)
\(=>\frac{x+2}{10^{10}}+\frac{x+2}{11^{11}}-\frac{x+2}{12^{12}}-\frac{x+2}{13^{13}}=0\)
\(=>\left(x+2\right).\left(\frac{1}{10^{10}}+\frac{1}{11^{11}}-\frac{1}{12^{12}}-\frac{1}{13^{13}}\right)=0\)
Vì \(\frac{1}{10^{10}}>\frac{1}{11^{11}}>\frac{1}{12^{12}}>\frac{1}{13^{13}}\)
Nên \(\frac{1}{10^{10}}+\frac{1}{11^{11}}-\frac{1}{12^{12}}-\frac{1}{13^{13}}\)khác 0
Suy ra: x+2=0
x =0 - 2
x = -2
TICK NHA
tim so nguyen x biet :
4 - (27-3) = x - (13-4).
4 - (27-3) = x - (13-4).
4 - 24 = x - 9 hay x -9 = 4 - 24
x - 9 = -20
x = -20 + 9
x = -11
4 - (27-3) = x - (13-4).
4 - 24 = x - 9
x - 9 = - 20
x = -11
4 - (27-3) = x - (13-4).
4 - 24 = x - 9
x - 9 = - 20
x = -11