+ Nếu x < 2, ta có: (2 - x) - (5 - x) = 2x
=> -3 = 2x
=> x = -3/2, thỏa mãn x < 2
+ Nếu 2 < hoặc = x < 5, ta có: (x - 2) - (5- x) = 2x
=> 2x - 7 = 2x, vô lý
+ Nếu x > hoặc = 5, ta có: (x - 2) - (x - 5) = 2x
=> 3 = 2x
=> x = 3/2, không thỏa mãn x > hoặc = 5
Vậy x = -3/2
Thu gọn các biểu thức sau:
A = \(\left|x^2+2\right|+\left|-3x^2-2\right|-\left|-2x^2-2\right|\)
B = \(\left|2x-3\right|-\left|3x-2\right|-\left|4-2x\right|\) với x > 5
C = \(\left|3x-6\right|+\left|3x+10\right|\) với -2 < x < 2
D = \(\left|8-3x\right|+\left|x+2\right|\) với x < 2
E = \(\left|x-2\right|+\left|x-4\right|+\left|x-6\right|\) với x < 5
F = \(\left|\left(x-2\right)\left(x-4\right)\right|-\left|\left(4-x\right)\left(x-2\right)\right|\)
Tìm x thuộc Z biết
a. \(\left(x-1\right)\times\left(2x-4\right)=0\)
b. \(\left(x^2+5\right)\times\left(x-5\right)=0\)
c. \(\left(x^2+5\right)\times\left(x^2-2\right)=0\)
d. \(\left(x^2-1\right)\times\left(x^2-9\right)< 0\)
e. \(\left|x^2-2x\right|=x\)
g. \(\left|2x+1\right|+\left|x+8\right|=4x\)
Tìm x: \(\left(x-2\right)^3+3\left(2x-3\right)^2=\left(3+x\right)^3-5\left(1+3x\right)^2-\left(x-1\right)\left(3-x\right)\)
Tìm x: \(\left(2x-1\right)^2-4\left(x+2\right)^2=5\left(x-1\right)\left(x+2\right)-7x\left(x+1\right)\)
Tìm x: \(\left|x-5\right|+\frac{\left(x-1\right)\left(x-3\right)}{2}=\frac{\left(x+1\right)^2}{3}-\frac{\left(1-2x\right)^2}{4}\)
Tìm \(x\), biết :
a) \(\left(2x-3\right)-\left(x-5\right)=\left(x+2\right)-\left(x-1\right)\)
b) \(2\left(x-1\right)-5\left(x+2\right)=-10\)
tìm x biết
a, ( 2x - 3 ) ( x + 1 ) <0
b, ( x - \(\frac{1}{2}\) ) ( x + 3) >0
c,\(\frac{3}{\left(x+3\right)\left(x+5\right)}+\frac{5}{\left(x+5\right)\left(x+10\right)}+\frac{7}{\left(x+10\right)\left(x+17\right)}=\frac{x}{\left(x+2\right)\left(x+17\right)}\)
biết không thuộc { -2, -5 ,-10 ,-17 }
Thu gọn :
a) \(2\left(x^2-3x+5\right)-4\left(x^2+x-1\right)\)
b) \(-5\left(x^2-3\right)+2\left(x-5\right)-4\left(x^2+x-5\right)\)
c) \(\frac{1}{2}\left(2x^2-4x+1\right)-\left(x^2+\frac{1}{2}\right)\)
Tìm x biết :
1) \(\left|x\right|\) + x = 2
2) \(\left|x-1\right|\) + x = 2
3) \(\left|2x+4\right|\) = 5 - x
4) \(\left|x-1\right|\) + \(\left|x-3\right|\) = 2
5) \(\left|x-2\right|\) + \(\left|x+1\right|\) = 1
6) \(\left|2x-1\right|\) + \(\left|2x+1\right|\) = 2
Mọi người lm giúp mk với đi ạ
1. Tìm x ϵ Q sao cho:
a) (2x-3). (x+1) < 0.
b) \(\left(x-\frac{1}{2}\right).\left(x+3\right)\)> 0.
2. Tính:
S=\(\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{999.1001}\)
3. Tìm x: Biết x không thuộc{-2; -5; -10; -17}
\(\frac{3}{\left(x+2\right).\left(x+5\right)}+\frac{5}{\left(x+5\right).\left(x+10\right)}+\frac{7}{\left(x+10\right).\left(x+17\right)}=\frac{x}{\left(x+2\right).\left(x+17\right)}\)
