C

1,6-|x-0,8|=0,4

=>|x-0,8|=1,6-0,4

=>|x-0,8|=1,2

x-0,8=1,2=>x=2

x-0,8=-1,2=>x=-0,4

I spent three hours to do my homework last night

c

D

1 yes, i often walk eveyday

2 yes, when i was a child i walked much 

3 i think people walk less than before because they have to work more and they have means of transportation to go

xét tg ABC

MA=MB,NB=NC

=>MN đườngg trung bình tg ABC

=>MN//AC

xét tứ giác AMNC

MN//AC

=>tứ giác AMNC là hình thang

a) x²-7x(x-4)=16

 x²-16-7x(x-4)=0

(x-4)(x+4)-7x(x-4)=0

(x-4)(x+4-7x)=0

(x-4)(-6x+4)=0

=>x=4 hoặc x=2/3

b) (x+5)^2-3(x+1)=22

x²+10x+25-3x-3=22

x²+10x-3x=22+3-25

x²+7x=0

x(x+7)=0

=>x=0 hoặc x=-7