(-3,4) : (-1,7) - 0,2

=  2 - 0,2 = 1,8

B

B

a, 3( x-3y )

b, 5xy( 3x-2y )

c, ( 5xy+ 10y^2 ) + ( 2x+4y )

= 5y( x+2y ) + 2(x+2y)

= ( x+2y )(5y+2)

d, ( 9x^2 + 6x + 1 ) - 4y^2

= ( 3x+1)^2 - 4y^2

= ( 3x+1)^2 - (2y)^2

= (3x+2y+1)(3x-2y+1)

e, x^2 +4x+4-1

= ( x^2+4x+4) -1

= ( x+2)^2 - 1

= ( x+2+1)(x+2-1)

= ( x+3 ) ( x+1)

g, (x^2 -2x +1) - (x-1)

= ( x-1)^2 - (x-1)

= x-1

37. He is interested in helping homeless people.

39. The weather was cold we didn't go fishing.

SO2 , CACO3 , CO , NH3

A

1. The flower watered by my father every moning.

2. Fiona was invited to his birthday party by John last night.

3. The dinner is being prepared by her mother in the kitchen.

4. Our teeth should be cleaned twice a day.

5. The English grammar have been explained by our teachers.