Thầy cô giúp e với ạ
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2.1
ĐKXĐ: \(x\ge-\dfrac{1}{16}\)
\(x^2-x-20-2\left(\sqrt{16x+1}-9\right)=0\)
\(\Leftrightarrow\left(x-5\right)\left(x+4\right)-\dfrac{32\left(x-5\right)}{\sqrt{16x+1}+9}=0\)
\(\Leftrightarrow\left(x-5\right)\left(x+4-\dfrac{32}{\sqrt{16x+1}+9}\right)=0\) (1)
Do \(x\ge-\dfrac{1}{16}\Rightarrow\left\{{}\begin{matrix}\dfrac{32}{\sqrt{16x+1}+9}< \dfrac{32}{9}\\x+4\ge-\dfrac{1}{16}+4=\dfrac{63}{16}>\dfrac{32}{9}\end{matrix}\right.\)
\(\Rightarrow x+4-\dfrac{32}{\sqrt{16x+1}+9}>0\)
Nên (1) tương đương:
\(x-5=0\)
\(\Leftrightarrow x=5\)
Câu 2.2, 2.3 đề lỗi không dịch được
22 kidnapper
23 foggy
24 southern
25 decision
26 entertainment
27 information
28 pronounciation
29 departure
30 demonstration
31 economically
32 intelligence
33 fearful
34 accidentally
35 employees
76 successful
77 richness
78 musician
79 pollution
80 saving
81 unpleasant
82 misinformed
83 favorable
84 encouragement
85 qualified
86 traditionally
87 dressed
88 invention
89 musician
90 ability
91 nervousness
92 confidence
93 independently
94 endlessly
95 breakthrough
96 lessen
97 penniless
98 pursuit
99 Contended
100 situation
101 expectation
102 variety
103 logical
37 distinguish
38 illiteracy
39 energetic
40 disconnected
41 anxiety
42 mysteriously
43 significant
44 frightening
45 repeatedly
46 cancellation
47 disastifying
48 products
49 disagree
50 typicallu
51 socialize
52 vegetarian
53 entrance
54 modernized
55 income
52 vegetarians
53 entrance
54 modernized
55 income
56 opposite
57 Comsumers
58 disatisfaction
59 Conservation
60 practices (nghe k hợp lắm)
nếu có thêm use thì là practical
61 inspiration
62 unfriendly
63 disagree
64 comparision
65 bored
66 unsuccessful
67 readiness
68 poverty
69 carelessly
70 mountainous
71 unemployment
72 examination
73 multinational
74 positivity
75 respectful
a b c c b a b d d a c d b c