Q 1: Bài tập chia động từ
1. They ________ (talk) on the phone when I walked into the room.
2. The sun .......................(rise) in the east every morning. 3. Sarah ________ (do) her homework at her desk all afternoon.
4. Look! They (run) .......................... in the park. 5. What ________ (you / eat) for dinner last night?
6. . What ________ (you / do) at 6 o'clock last night? 7. It ________ (snow) heavily when we left the house.
While the teacher was writing on the board, the students _______ (text) under their desks.
8. The music lesson (start) ......................... at 8:00 am. 9. Messi (play) .............................. football six times a week. 10. The birds ________ (sing) beautifully when we went for our walk in the park.
Q2. Viết lại câu sử dụng trạng từ chỉ tần suất trong ngoặc
1. My friends and I go to the cinema. (sometimes)
2. It rains here in the summer. (rarely)
3. My brother does his homework in the evenings. (usually)
4. I get up early for school. (always)
5. My family eats dinner together. (often)
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Bài 5A:
a) Ta có: \(\widehat{aAe}=\widehat{bBA}=100^o\)
\(\Rightarrow a//b\)
\(\Rightarrow\widehat{gCc}=\widehat{CDd}\) (đồng vị)
\(\widehat{CDd}=135^o\)
Mà: \(x+\widehat{CDd}=180^o\) (kề bù)
\(\Rightarrow x=180^o-\widehat{CDd}=180^o-135^o=45^o\)
b) Xét tứ giác MNPQ có:
\(\widehat{QPM}+\widehat{PQN}+\widehat{PMN}+\widehat{QNM}=360^o\)
\(\Rightarrow2y+y+90^o+90^o=360^o\)
\(\Rightarrow3y=180^o\)
\(\Rightarrow y=\dfrac{180^o}{3}=60^o\)
Bài 3A:
Ta có: \(\widehat{A_1}+\widehat{B_3}=80^o+100^o=180^o\)
Mà hai góc này ở vị trí trong cùng phía
\(\Rightarrow a//b\)
Bài 4A:
\(a//b\Rightarrow\widehat{A_2}=\widehat{bBA}\)
\(\Rightarrow\widehat{bBA}=75^o\)
Mà: \(\widehat{bBA}+\widehat{B_3}=180^o\) (kề bù)
\(\Rightarrow\widehat{B_3}=180^o-\widehat{bBA}=180^o-75^o=105^o\)
|x - 2| = x
*) Với x < 2, ta có:
|x - 2| = x
2 - x = x
x + x = 2
2x = 2
x = 1 (nhận)
*) Với x ≥ 2, ta có:
|x - 2| = x
x - 2 = x
x - x = 2
0x = 2 (vô lý)
Vậy x = 1
|\(x\) - 2| = \(x\) ( \(x\) > 0) ⇒\(\left[{}\begin{matrix}x-2=-x\\x-2=x\end{matrix}\right.\) \(\Rightarrow\) \(\left[{}\begin{matrix}2x=2\\-2=0\left(ktm\right)\end{matrix}\right.\)⇒ \(x\) = 1 > 0(tm)
Vậy \(x\) = 1
Số hữu tỉ là số có thể viết được dưới dạng p/số á bạn.
VD: -5,6 ; 8 ; 25/10 ;...
Số hữu tỉ là số có thể viết dưới dạng \(\dfrac{a}{b}\) trong đó a; b \(\in\) Z; b ≠ 0
f; (\(x\) + 4).(\(x-2\)) = 0
\(\left[{}\begin{matrix}x+4=0\\x-2=0\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=-4\\x=2\end{matrix}\right.\)
Vậy \(x\) \(\in\) {-4; 2}
g; (\(x\) - 2).(\(x\) + 3) < 0
\(x\) - 2 = 0 ⇒ \(x\) = 2; \(x\) + 3 = 0 ⇒ \(x\) = -3
Lập bảng ta có:
| \(x\) | - 3 2 |
| \(x-2\) | - - 0 + |
| \(x\) + 3 | - 0 + + |
| (\(x-2\)).(\(x+3\)) | + 0 - 0 + |
Theo bảng trên ta có -3 < \(x\) < 2
Vậy -3 < \(x\) < 2
e) \(x^2-3x=0\)
\(\Leftrightarrow x\left(x-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x-3=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=3\end{matrix}\right.\)
Vậy: ...
f) \(\left(x+4\right)\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+4=0\\x-2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-4\\x=2\end{matrix}\right.\)
Vậy: ...
g) \(\left(x-2\right)\left(x+3\right)< 0\)
TH1: \(\left\{{}\begin{matrix}x-2>0\\x+3< 0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x>2\\x< -3\end{matrix}\right.\)
\(\Rightarrow x\in\varnothing\)
TH2: \(\left\{{}\begin{matrix}x-2< 0\\x+3>0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x< 2\\x>-3\end{matrix}\right.\)
\(\Rightarrow-3< x< 2\)
Vậy: ...
h) \(\left(x-1\right)\left(x+2\right)>0\)
TH1: \(\left\{{}\begin{matrix}x-1>0\\x+2>0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x>1\\x>-2\end{matrix}\right.\)
\(\Rightarrow x>1\)
TH2: \(\left\{{}\begin{matrix}x-1< 0\\x+2< 0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x< 1\\x< -2\end{matrix}\right.\)
\(\Rightarrow x< -2\)
Vậy: ...
a) \(3\left(2x+7\right)-2x=9\Leftrightarrow6x+21-2x=9\)
\(\Leftrightarrow4x+21=9\)
\(\Leftrightarrow4x=9-21=-12\)
\(\Leftrightarrow x=\dfrac{-12}{4}=-3\)
Vậy: ...
b) \(\left[\left(7x-4\right):2-2\right]\cdot13=221\)
\(\Leftrightarrow\left(7x-4\right):2-2=\dfrac{221}{13}=17\)
\(\Leftrightarrow\left(7x-4\right):2=17+2\)
\(\Leftrightarrow\left(7x-4\right):2=19\)
\(\Leftrightarrow7x-4=19\cdot2=38\)
\(\Leftrightarrow7x=42\)
\(\Leftrightarrow x=\dfrac{42}{7}=6\)
Vậy: ...
c) \(x^2-9=0\)
\(\Leftrightarrow x^2=9\)
\(\Leftrightarrow x=\pm\sqrt{9}\)
\(\Leftrightarrow x=\pm3\)
Vậy: ....
d) \(5< x^2< 16\)
\(\Leftrightarrow\left\{{}\begin{matrix}x^2>5\\x^2< 16\end{matrix}\right.\)
Với \(x^2>5\Rightarrow\left[{}\begin{matrix}x< -\sqrt{5}\\x>\sqrt{5}\end{matrix}\right.\) (1)
Với \(x^2< 16\Rightarrow-4< x< 4\) (2)
Từ (1) và (2) \(\left[{}\begin{matrix}-4< x< -\sqrt{5}\\\sqrt{5}< x< 4\end{matrix}\right.\)
Q1:
1. were talking
2. rises
3. did
4. are running
5. did you eat
6. were you doing
7. was snowing
8. were texting
9. starts
10. plays
11. were singing
Q2:
1. My friends and I sometimes go to the cinema.
2. It rarely rains here in the summer.
3. My brother usually does his homework every evening.
4. I always get up early for school.
5. My family often eats dinner together.
1. They ___were talking_____ (talk) on the phone when I walked into the room.
2. The sun .......rises................(rise) in the east every morning.
3. Sarah ____does____ (do) her homework at her desk all afternoon.
4. Look! They (run) ............are running.............. in the park.
5. What ____did you eat____ (you / eat) for dinner last night?