Tìm x , biết:
x(x + 2015 ) + 2x + 4030 = 0
tìm x biết:x*7+x*9-x-x*5=790
x * 7 + x * 9 - x - x * 5 = 790
x * 7 + x * 9 - x * 1 - x * 5 = 790
x * ( 7 + 9 - 1 - 5 ) = 790
x * 10 = 790
x = 79
79 nha ban minh giai tren Violympic toan dung
14. Giải các phương trình:
a, 2x+1/9+2x+2/8+2x+3/7+...+2x+8/2+2x+9/1+9=0
b, x-1/2015+x-2/2014+x-3/2013+... +x-2014/2+x=4030
a: =>\(\left(\dfrac{2x+1}{9}+1\right)+\left(\dfrac{2x+2}{8}+1\right)+...+\left(\dfrac{2x+9}{1}+1\right)=0\)
=>2x+10=0
=>x=-5
b: \(\Leftrightarrow\left(\dfrac{x-1}{2015}-1\right)+\left(\dfrac{x-2}{2014}-1\right)+...+\left(\dfrac{x-2014}{2}-1\right)+\left(x-2016\right)=0\)
=>x-2016=0
=>x=2016
tìm số nguyên x, biết:x/4=21/28
\(\frac{x}{4}=\frac{21}{28}\)
\(\Rightarrow x=\frac{21.4}{28}\)
\(\Rightarrow x=3\)
\(Tacó:\frac{x}{4}=\frac{21}{28}nênx=\frac{4.21}{28}\\ Suyrax=3\)
\(\frac{x}{4}\)=\(\frac{21}{28}\)
\(\frac{x}{4}\)=\(\frac{3}{4}\)suy ra x=3
Các bạn giúp mình với,mai mình thi rồi.Tìm x:
(2015*x-4030)^2017=(2015*x-4030)^2018
\(\left(2015.x-4030\right)^{2015}=\left(2015.y-4030\right)^{2016}\)
Tìm x biết: (2x+1)+(2x+2)+...+(2x+2015)=0
(2x + 1) + (2x + 2) + ... + (2x + 2015) = 0
=> 2015.2x + (1 + 2 + 3 + ... + 2015) = 0
=> 4030x + (2015 + 1).2015 : 2 = 0
=> 4030x = -2031120
=> x = -504
tìm n thuộc N biết:x^3y^4+2x^3y^4+3x^3y^4+.........+ n.x^3y^4=820x^3y^4
(1+1/2+1/3+........+1/205)*x+2015=2016/1+2017/2+2018/3+......+4030/2015
tìm x
Tìm x biết:
\(\left(1+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{2015}\right)x+2015=\frac{2016}{1}+\frac{2017}{2}+...+\frac{4029}{2014}+\frac{4030}{2015}\)