tim x thuoc z biet
a) (x-1)(x+2) < 0
b) (x+3)(x-5) > 0
1) Tim a, b thuoc Q biet: a-b=2(a+b)=a:b
2) Tim x thuoc Q sao cho: (x-1)(x+3)<0
tim x thuoc z biet
a,1/(1×2) + 1/(2×3) + ... + 2/(x(x+1)) = 2005/2010
tim cac so x,y,z thuoc Q biet rang (x+y):(5-z):(y+z):(y+9)=3:1:2:5
tim x thuoc z biet /x+1/ +/x-2/+/x+7/=5x-10
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 thuoc z biet /x+1/ +/x-2/+/x+7/=5x-10
tim x thuoc z biet (x-5)^x+1-(x-5)^x+5
