b c c b c c a d a

C C B C C A D A

trả lời là :

b, c, c, b, c, c, a, d, a

Bài 2: 

b: =>(x-5)(x+3)=0

hay x=5 hoặc x=-3

C A B C D C B C A D 

13,15

c

C

a: =

b: <

a)   -4/7+3/-7 = -1

b) -15/22+-3/22 <-8/11

a)\(\dfrac{7}{3}\)    b)\(\dfrac{-16}{7}\)

\(C1\)
\(a.6\sqrt{5}+\sqrt{5}-12\sqrt{5}=-7\sqrt{5 }\)
\(b.\left|2-\sqrt{3}\right|+\sqrt{3}-1-6\sqrt{3}=2-\sqrt{3}+\sqrt{3}-1-6\sqrt{3}=1-6\sqrt{3}\)
C2
a. ĐK: x≤\(\dfrac{4}{3}\)
4-3x=64<=>3x=-60<=>x=-20
b. ĐK: x≥2
\(< =>2\sqrt{x-2}-4\sqrt{x-2}=-1< =>-2\sqrt{x-2}=-1< =>\sqrt{x-2}=\dfrac{1}{2}< =>x-2=\dfrac{1}{4}< =>x=\dfrac{9}{4}\)
c. ĐK: x≥0
\(< =>2x-4\sqrt{x}+\sqrt{x}-2=7< =>2x-3\sqrt{x}-9=0< =>x=9\)