When you hear the woek '' bank'' what do you think ? A .....place ... to put money? The land on the edge of a river? to depend on something or someone? If you choose any of ....these.... things you're right. Why? Because words often have ......more........ than one meaning. The tricky part is fiuring out ....which...... meaning is appropriate.

Choosing the correct meaning of a word depends on ....two...... things. First, it depends on the words and .....sentence....... sorrounding your particular word. The other words and sentences give you context clues. ......Second...., the meaning depends on how the word is ......used..... in the sentence. Is it a noun, a verb, ......an...... adjective or a part of a phrase? Knowing the word's part of speech will .....help........ you discover the word's precise meaning.

a) Xét \(\Delta\) ABH và \(\Delta\)ACK

Ta có: Góc A chung

AB = AC

góc AHB = góc AKC ( =90^o )

=> \(\Delta\)AKC = \(\Delta\)AHB ( ch-gn)

=> BH = CK

=> AK = AH

=>\(\dfrac{AK}{KB}\) = \(\dfrac{AH}{HB}\)

=> HK // BC

b) Xét \(\Delta\)IAC và \(\Delta\)HBC

Ta có : Góc I = Góc H (=90⁰)

Góc C chung

=> \(\Delta\)IAC \(\infty\) \(\Delta\)HBC (g.g)

Xét \(\Delta\)AKH và \(\Delta\)ABC

Ta có:

\(\dfrac{AK}{AB}\) = \(\dfrac{AH}{AC}\) ( do HK // BC )

Góc A chung

=> \(\Delta\)AKH \(\infty\) \(\Delta\)ABC (c.g.c)

c) Tự thay vào làm nhé!!

\(2011^{2002}=2011.2011....2011=\left(......1\right)\) Tận cùng là 1 (1)

\(2009^{2000}=\left(.....1\right)\left(.....1\right).......\left(.....1\right)=.....1\) tận cùng là 1 (2)

Từ (1) và (2) = > A có chữ số tận cùng là 1 + 1 = 2

=> A không chia hết cho 5