tim x biet
(2x+1)^3=10^2+5^2
Những câu hỏi liên quan
Tim xthuoc Z biet:
1,|2x-5|-|2x+9|=0
2,|x+1|-|x+2|-|3-x|=7
3,|2x+3|+|3x+2|-|4-x|=10
Tim x biet:
a.2|2x-3|=1/2
b.(x-1)^2=9/16
c.3/5(x-5/6)-1/2(3/2-1)=-1/4
d.1/3+1/6+1/10+......+2/x(x+1)=2015/2016
a) \(\Leftrightarrow\left|2x-3\right|=\frac{1}{4}\Leftrightarrow\orbr{\begin{cases}x\ge\frac{3}{2}\mid:2x-3=\frac{1}{4}\Rightarrow2x=\frac{13}{4}\Rightarrow x=\frac{13}{8}\left(TM\right)\\x< \frac{3}{2}\mid:3-2x=\frac{1}{4}\Rightarrow2x=\frac{11}{4}\Rightarrow x=\frac{11}{8}\left(TM\right)\end{cases}.}\)
b) \(\Leftrightarrow\left|x-1\right|=\frac{3}{4}\Leftrightarrow\orbr{\begin{cases}x\ge1\mid:x-1=\frac{3}{4}\Rightarrow x=\frac{7}{4}\left(TM\right)\\x< 1\mid:1-x=\frac{3}{4}=>x=\frac{1}{4}\left(TM\right)\end{cases}}\)
c) \(\frac{3}{5\left(x-\frac{5}{6}\right)}-\frac{1}{2\left(\frac{3}{2}-1\right)}=-\frac{1}{4}\Leftrightarrow\frac{3}{\frac{5\left(6x-5\right)}{6}}-\frac{1}{2\cdot\frac{1}{2}}=-\frac{1}{4}\Leftrightarrow\frac{18}{5\left(6x-5\right)}=-\frac{1}{4}+1\)
\(\Leftrightarrow\frac{18}{5\left(6x-5\right)}=\frac{3}{4}\Leftrightarrow6x-5=\frac{24}{5}\Leftrightarrow6x=\frac{49}{5}\Leftrightarrow x=\frac{49}{30}\)
d) \(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{2}{x\left(x+1\right)}=\frac{2015}{2016}\)
\(\Leftrightarrow\frac{2}{2\cdot3}+\frac{2}{3\cdot4}+\frac{2}{4\cdot5}+...+\frac{2}{x\left(x+1\right)}=\frac{2015}{2016}\)
\(\Leftrightarrow2\cdot\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{x}-\frac{1}{x+1}\right)=\frac{2015}{2016}\)
\(\Leftrightarrow2\left(\frac{1}{2}-\frac{1}{x+1}\right)=\frac{2015}{2016}\Leftrightarrow2\cdot\frac{x+1-2}{2\left(x+1\right)}=\frac{2015}{2016}\Leftrightarrow\frac{x-1}{x+1}=\frac{2015}{2016}\)
\(\Leftrightarrow2016x-2016=2015x+2015\Leftrightarrow x=2015+2016=4031\)
Vậy x = 4031.
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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
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tim x biet:10+(2x -1) mu 2 chia 3
Tim x biet.
a/x+5+x-7+x-9=x-5+x-2
b/9(2x-3)+5=4(4-1)-8
c/2=-(×-1)^5+34
d/7=-|x-5|+10
tim x biet : a,-12/21×x + 3/7=-4/3, b, 2x +-3^2=5/4 , c, 75% x- 2/5=3/10, d, (3x-2)×(x+7)
tim x biet (2x-3)^2-4(x+1)^2=5
tim 2 so tu nhien x va y biet 1) (2x+1)x(y-3)=10 2) (x+1)x(2y-5)=143 3) (3x-2)x(2y-3)=1 4) (x+1)x(2y-1)=12
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)