6. Tìm GTNN

P= |2x-8|+|2x-10|

Q= |x-3|+|2y-5|

5. Tìm GTLN

a) M= 7-4|x+3|

b) N= \(\dfrac{18}{\left|x-2\right|+9}\)+5

3. Tìm x, biết:

a) 2x + 8 ≤ 0 

b) 4x-7 ≥ 2x -5

c) (2x-8)(15-3x)>0

d) (10-2x)(8+2x)≤0

4. Tìm GTNN.

a) P= 2|2x-5|+7

b) Q=-4+3|x-7|

Tìm x:

(2x-\(\dfrac{1}{2}\))(\(\dfrac{5}{4}\)-3x)=0

Tìm x, y ϵ Z

(3x-5)(2x+1) = 12

Tìm x, y ϵ Z.

 \(\dfrac{4}{x}-\dfrac{y}{2}=\dfrac{1}{4}\)

 Tìm x, y ϵ Z.

b) \(\dfrac{1}{x}-\dfrac{y}{2}=\dfrac{1}{4}\)

d) (3x-5)(2x+1)=12

M = 7.8+8.9+9.10+...+19.20

11. Tìm x

a) (2x-8)(10+2x)≥0

b) (|x|+5)(x-3)<0