tim x biet\(a^2x+x=2a^2-3\)
Cho A = 3 +3^2 + 3^3 + .....+ 3^2008. tim x biet 2a+3=3^x
\(A=3+3^2+...+3^{2008}\)
\(3A=3.\left(3+3^2+...+3^{2008}\right)\)
\(3A-A=\left(3^2+3^3+...+3^{2009}\right)-\left(3+3^2+...+3^{2008}\right)\)
\(2A=3^{2009}-3\)
\(2A+3=3^{2009}-3+3\)
\(2A+3=3^{2009}\)
Vì \(2A+3=3^x\)hay \(3^{2009}=3^x\)
\(\Rightarrow x=2009\)
Thank you to kick me ooooooooooooooooooo
a, Tim x biet:/x-2/+/3-2x/=2x+1
b, Tim x,y thuoc Z biet:xy+2x-y=5
c, tim x,y,z, biet :2x=3y;4y=5zva 4x-3y+5z=7
a,tim x biet |x-2|+|3-2x|=2x+1
b,tim x,y thuoc Z biet xy+2x-y=5
c, tinh A=(1-1/15)(1-1/21)(1-1/28).....(1-1/210)
tim x biet
a)x2+/x-3/=x2+/2x-3/
B1:tim cac so nguyenx,y biet:
X,y + 2.x- 3y= 11
B2 tim x biet
A -15.(x+2)+7.(2x-3)=(-5) . (+10)
Giai gap minh nhe
\(-15.\left(\chi+2\right)+7.\left(2\chi-3\right)=\left(-5\right).10\)
\(\Rightarrow-15\chi+\left(-30\right)+14\chi-21=-50\)
\(\Rightarrow\left(-15\chi+14\chi\right)=-50+30+21\)
\(\Rightarrow\chi=1\)
HTDT
tim x biet : (2x+3)^2x - 2*(2x+3)*(2x-5)+(2x-5)^2=x^2+6x+64
\(\Leftrightarrow\left(2x+3-2x+5\right)^2=x^2+6x+64\)
=>x^2+6x=0
=>x(x+6)=0
=>x=0 hoặc x=-6
tim x biet 2x+1/x-2=2x-3/x+6
tại sao không ai làm nhỉ?
(2x+1)(x+6) = ((X-2)(2X-3)
2x2 +12x+x +6 = 2x2 -3x-4x +6
20x =0
x =0
( 1 chữ cũng là thầy, nửa chữ cũng là thầy)
Tim x biet:|x-2|+|3-2x|=2x+1
\(\Leftrightarrow\left|x-2\right|+\left|2x-3\right|=2x+1\)
Trường hợp 1: x<3/2
Pt sẽ là 3-2x+2-x=2x+1
=>-3x+5=2x+1
=>-5x=-4
hay x=4/5(nhận)
Trường hợp 2: 3/2<=x<2
Pt sẽ là 2x-3+2-x=2x+1
=>2x+1=x-1
=>x=-2(loại)
Trường hợp 3: x>=2
Pt sẽ là x-2+2x-3=2x+1
=>3x-5=2x+1
hay x=6(nhận)
|(x+1/2).|2x-3/4||=2x-3/4 tim x biet