1 A

2 D

3 A

4 C

5 C

6 A

7 A

8 B

9 D

10 A

11 D

12 D

13 C

1 in

2 at

3 At

4 during

5 at

6 at

7 for

8 during

9 on

10 for

1 in

2 at

3 At

4 during

5 at

6 at

7 for

8 during

9 on

10 for

a: Δ=(m-2)^2-4(m-4)

=m^2-4m+4-4m+16

=m^2-8m+20

=m^2-8m+16+4

=(m-2)^2+4>=4>0

=>Phương trình luôn có 2 nghiệm pb

b: x1^2+x2^2

=(x1+x2)^2-2x1x2

=(m-2)^2-2(m-4)

=m^2-4m+4-2m+8

=m^2-6m+12

=(m-3)^2+3>=3

Dấu = xảy ra khi m=3

refer

1/ I like table tennis and that’s why I spend a lot of time on that game.
=>I spend a lot of time on table tennis because I like it.
2/ Because the weather was cold, we had to cancel our picnic.
=> The weather was cold, so we had to cancel our picnic.
3/ I won’t forget to phone her. You know, I like her so much.
=> You know I like her so much so I won't forget to phone her
4/ They tried their best to complete the course and that was why they passed.
=> they tried their best to complete the course, so they passed
5/ I love my city so much, so I think I will stay and work here in my city.
=> I think I will stay and word in my city because I love it so much.

1 Because I like table tennis, I spend a lot of time on that game

2 The weather was so cold that we had to cancel our picnic

3 I won't forget to phone her because I like her so mich

4 They pass the course because they tried their best to complete the course

5 Because I love my city so much, I think I will stay and work here in my city

3.B (thì HTHT với dấu hiệu yet)

4. B

5. B (wish S Ved: ước trong iện tại)

6. D (thì QKĐ với dấu iệu Last night)

a: Xét (O) có

ΔADB nội tiếp

AB là đường kính

Do đó: ΔADB vuông tại D

=>AD⊥BC tại D

Xét tứ giác AHDC có \(\hat{AHC}=\hat{ADC}=90^0\)

nên AHDC là tứ giác nội tiếp

b: AHDC nội tiếp

=>\(\hat{AHD}+\hat{ACD}=180^0\)

mà \(\hat{AHD}+\hat{MHD}=180^0\) (hai góc kề bù)

nên \(\hat{MHD}=\hat{ACD}=\hat{ACB}\)

Xét ΔOAC vuông tại A có AH là đường cao

nên \(OH\cdot OC=OA^2\)

=>\(OH\cdot OC=OB^2\)

=>\(\frac{OH}{OB}=\frac{OB}{OC}\)

Xét ΔOHB và ΔOBC có

\(\frac{OH}{OB}=\frac{OB}{OC}\)

góc HOB chung

Do đó: ΔOHB~ΔOBC

=>\(\hat{OHB}=\hat{OBC}=\hat{ABC}\)

mà \(\hat{OHB}+\hat{MHB}=\hat{OHM}=90^0\) và \(\hat{ABC}+\hat{ACB}=90^0\) (ΔABC vuông tại A)

nên \(\hat{MHB}=\hat{ACB}\)

=>\(\hat{MHB}=\hat{DHM}\)

=>HM là phân giác của góc DHB

a) Dấu hiệu : Điểm kiểm tra Toán của mỗi học sinh trong lớp 7A1 

Có tất cả 40 giá trị

bn tự lập bảng tần số nha mik k biết lập ở trên này

3.15:
EF vuông góc MH

NP vuông góc MH

Do đó: EF//NP

3.17:

góc yKH+góc H=180 độ

mà hai góc này là hai góc ở vị trí trong cùng phía

nên Ky//Hx