Các bạn giúp mk giải ý f, g vs ạ
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f(2)=g(0)
=> c=5
f(1)=g(1)
=> a+b+c=2 mà c=5 => a+b=-3 (1)
f(-1)=g(3)
=>9a+3b+c=2 mà c=5= > 9a+3b=-3=> 3a+b=-1(2)
(2)-(1) ta được:
2a=2=>a=1=> b=-4
VẬy g(x)=x^2-4x+5
t i ck ủng hộ tui nha
PTHH: 2Al + 6HCl → 2AlCl3 + 3H2
PTHH: Mg(OH)2 + 2HCl → MgCl2 + 2H2O
PTHH: Fe2O3 + 6HCl → 2FeCl3 + 3H2O
PTHH: K2O + 2HCl → 2KCl + H2O
Lần sau em đăng câu hỏi đúng box để mọi người hỗ trợ nha
14 Lan asked Thu where she could find the new cartoons
15 Phong asked Lan if their teacher asked them to clean up the room
16 She asked me to give her some money
17 Tam asked Thu if she would be there for five days
18 The students asked their teacher to give them easier homework
19 She asked her husban if they needed some help
20 Lan asked Hoa is she might have a look at her picture
21 Lam asked Lan if their class would take part in that competition
42 rains
43 gives
44 returns
45 will go
46 study
47 would try
48 has just published
49 has traveled
50 wouldn't lose/didn't lose/hadn't lost
51 didn't rain
52 hot
53 Have you ever been - have been
54 could
55 wants - study
56 listening
57 rings
58 took part
59 was spoken
60 do - to learn
I
1 C
2 D
3 D
4 A
5 B
II
6 C
7 A
8 A
9 A
10 D
11 C
12 C
13 C
14 D
15 D
16 D
17 C
18 B
19 C
20 B
III
21 painting => being painted
22 she => bỏ
23 doesn't => isn't
24 at => in
25 didn't => wouldn't
a) Ta có: \(A=\dfrac{x^2+x}{x^2-2x+1}:\left(\dfrac{x+1}{x}-\dfrac{1}{1-x}+\dfrac{2-x^2}{x^2-x}\right)\)
\(=\dfrac{x\left(x+1\right)}{\left(x-1\right)^2}:\dfrac{x^2-1+x+2-x^2}{x\left(x-1\right)}\)
\(=\dfrac{x\left(x+1\right)}{\left(x-1\right)^2}\cdot\dfrac{x\left(x-1\right)}{x+1}\)
\(=\dfrac{x^2}{x-1}\)
b) Ta có: |2x-5|=3
\(\Leftrightarrow\left[{}\begin{matrix}2x-5=-3\\2x-5=3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=2\\2x=8\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\left(loại\right)\\x=4\left(nhận\right)\end{matrix}\right.\)
Thay x=4 vào A, ta được:
\(A=\dfrac{4^2}{4-1}=\dfrac{16}{3}\)