4 If you aren't alert, you computer will be infected with viruses

5 If we use much pesticide on vegetables, they will become poisonous

9 Because Nam needs to improve his social skills, he attends the activity

11 How about using public buses instead of motorbike 

12 They enjoy protecting the environment unpolluted 

15 Mr Brown was disappointed that his son didn't write to him

D -> the weekend

11.

$=-a(x+t)+b(x+t)=(x+t)(-a+b)=(b-a)(x+t)$

12.

$=a(m-6)-5ab(m-6)=a(m-6)(1-5b)$

13.

$=\frac{2}{5}x(4-y)+\frac{2}{5}y(4-y)$

$=\frac{2}{5}(4-y)(x+y)$

14.

$=2m(x-y)-12m^3(x-y)$

$=2m(x-y)(1-6m^2)$

15.

$=14a^2(-x+2y)+7a(-x+2y)$

$=7a(-x+2y)(2a+1)$

dung roi

yes

đúng rùi'-'

Bài 12: 

a: Xét ΔABM và ΔACN có

AB=AC

\(\widehat{ABM}=\widehat{ACN}\)

BM=CN

Do đó: ΔABM=ΔACN

mik quên mất, làm hộ mik câu 1,11 và 12 nhé. cảm ơn mn rất nhiều

# ~Hok tốt~

11.

ngay thu nhat : 600m vai

ngay thu hai: 1050m vai

12.

a.4335m2

b.7225kg thoc

hoc tot

Tra loi:

1.A.23/27

hoc tot

là 9 bạn ơi

trình bày hộ tui zới

là 9 số bạn ơi