Ta co: |x2+x|+|(x+1).(x-2)|=0
Ma |x2+x|>=0,moi x thuoc R
|(x+1).(x-2)|>=0,moi x thuoc R
=>|x2+x|=0
|(x+1).(x-2)|=0
<=>x=-1
Vay x=-1.
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Ta co: |x2+x|+|(x+1).(x-2)|=0
Ma |x2+x|>=0,moi x thuoc R
|(x+1).(x-2)|>=0,moi x thuoc R
=>|x2+x|=0
|(x+1).(x-2)|=0
<=>x=-1
Vay x=-1.
a, Cho F(x) = a x+b . Tim a,b biet f(0) = 3 va F(2) =-1
b, Cho F(x) =a x+ b. Tim a,b biet F(1) = -1 va F(-2) = 8
c, Cho F(x) =a x +b .tim a,b biet F(0) = 1 va F(-2) = -9
tim x biet (x^2-1)(x^2-3)(x^2-5)(x^2-7)<=0
Tim x biet x^2+x+1=0
tim x thuoc Z biet x^3-x^2+x-1=0
tim x biet :
( 2-x ) x (4/5-x ) < 0
(x - 3/2) x ( 2x + 1 ) > 0
Tim x,y,z biet:
1)|x|+|1-x|+|x+2|=5
2)|x-1/2|+|y+2\3|+|x^2+xz|=0
TIM X BIET
(X+1) (X-2) < 0
tim x biet
a) [x-3].[x+2]=0
b) [x+1] . x < 0
Tim x biet
a) 3x+5-2(x+4)=4x+1/2b)(x+1)(x-1) <0c)(x-2)(x+2/3) >0