Question 1. Sa Pa / known / its / beautiful / mountains / valleys.

Sapa is known for its beautiful mountains and valleys

Question 2. British children / hang / small bells / gifts / Christmas trees.

British children hang small bells and gifts on Christmas trees

Question 3. If / you / not / take off / shoes, you / make / carpet / dirty.

If you don't take off your shoes, you will make the carpet dirty

Question 4. Our school / have / tradition / hold / talent show / every spring.

Our school have the tradition of holding a talent show every spring

Question 5. Vietnamese students / visit / Temple of Literature / pray / good luck.

Vietnamese students visit the Temple of Literature to pray for good luck

Question 1:Sapa is known for its beautiful mountains and valleys                                                                                                              Question 2:British children hang small bells and gifts on Christmas trees                                                                                                    Question 3:If you don't take off your shoes, you will make the carpet dirty                                                                                                    Questioon 4:Our school have the tradition of holding a talent show every spring                                                                                         Question 5:Vietnamese students visit the Temple of Literature to pray for good luck

a, Vì IK // EF

  ⇒ \(\dfrac{DI}{DE}\) = \(\dfrac{IK}{EF}\) (theo định lí talet)

  ⇒ \(\dfrac{DI}{DI+IE}\) = \(\dfrac{IK}{EF}\)

⇒ \(\dfrac{9,5}{9,5+28}\) = \(\dfrac{8}{x}\)

⇒ \(\dfrac{9,5}{37,5}\) = \(\dfrac{8}{x}\)

⇒ \(x\) = 8 : \(\dfrac{9,5}{37,5}\)

    \(x\) = 31,57 

Vì AB \(\perp\) BC;

   CD \(\perp\) BC

⇒ AB // CD (hai đường thẳng cùng vuông góc với một đường thẳng thứ ba thì song song với nhau)

⇒ \(\dfrac{AB}{CD}\) = \(\dfrac{BO}{OC}\)

   \(\dfrac{4,2}{x}\)  = \(\dfrac{3}{6}\)

   \(\dfrac{4,2}{x}\) =  \(\dfrac{1}{2}\)

     \(x\)    = 4,2 x 2 : 1 

      \(x\)   = 8,4

a) A = (x - 5)(x² + 5x + 25) - (x - 2)(x + 2) + x(x² + x + 4)

= x³ - 125 - x² + 4 + x³ + x² + 4x

= (x³ + x³) + (-x² + x²) + 4x + (-125 + 4)

= 2x³ + 4x - 121

b) Tại x = -2 ta có:

A = 2.(-2)³ + 4.(-2) - 121

= 2.(-8) - 8 - 121

= -16 - 129

= -145

c) x² - 1 = 0

x² = 1

x = -1; x = 1

*) Tại x = -1 ta có:

A = 2.(-1)³ + 4.(-1) - 121

= 2.(-1) - 4 - 121

= -2 - 125

= -127

*) Tại x = 1 ta có:

A = 2.1³ + 4.1 - 121

= 2.1 + 4 - 121

= 2 - 117

= -115