2x+23=2012-(2012-15)
2x+23=2012-2012+15
2x+23=15
2x=15-23
2x=-8
2x=-8:2
x=-4
2x+23=2012-2012-15
2x+23=-15
2x =-15-23
2x =-38
x =-38:2
vậy x =-19
Tim x biet: 1/10+1/15+1/21+.........+2/x.(x+1) = 2010/2012
tim x biet |2x - 1|<5
cho B= 1.2.3...2012[1+1/2+1/3+...+1/2012]
CMR B chia het cho 2013
2x + 23 = 2012 - ( 2012 - 15 )
tim x biet:
: \(\left(\frac{1}{1.2}+\frac{1}{3.4}+...+\frac{1}{99.100}\right).x=\frac{2012}{51}+\frac{2012}{52}+...+\frac{2012}{99}+\frac{2012}{100}\)
Tim x biet x^2014 + x^2012 + x^2010 + ... + x^2 + 1=
tim x,y,z biet x-y=2011,y-z=-2012,z+x=2013
tim x biet,(1+5+5^2+...+5^2011)|x-1|=5^2012-1
tim x biet
x + 4/2009 + x + 3 / 2010 = x + 2/2011 + x + 1/2012
tìm x biết /x+1/ + 2x^2012 - 3x^2012 -4x^2012+5x^2012 + 6x^2012 -7x^2012 -8x^2012 +...........+2013x^2012=2012
