a) ((a+b)>c) and ((b+c)>a) and ((a+c)>b)

b) (x<a1) or (x>a2)

c) (diem>=6) and (diem <8); 

(a*a<10) or (a mod 3=0)

a, (P) đi qua M(-3;18) 

<=> \(-18=9a\Leftrightarrow a=-2\)

Vậy với a = -2 thì (P) đi qua M(-3;18) 

b, bạn tự vẽ 

1, Ancester ship

2, It is a sacred place

3, Guests

4,Lullabies

5,cultivate

1,What do the Muong people often play?

2,Which is the largest ethnic group in VN

3, Whose the Cham children are named of?

4,What are the highlights of the Muong costume?

5,Where do the Muong live in with abundant......?

3^x+2.5^y=45^x

=>3^x+2.5^y=(3²)^x.5^x

=>\(\hept{\begin{cases}x+2=2x\\y=x\end{cases}}\Rightarrow x=y=2\)