MC questions(please show the steps)&Long questions(20 marks)

1. Simplify 7/5y 3/5y

= 10/5y
=2/y (B)

2.If x(k-1)=y, then k=

x(k-1)=y
(k-1) = y/x
k=y/x 1 (A)

3.Which of the following is an exampleof discrete data?

discrete解抽象
因為Population of a country無可能真係逐個數
只是粗略估計

所以係答案(D)

4.Expland 4x(8x^2-2x 7)
4x(8x^2-2x 7)
=32x^3-8x^2 28x

5(a).Given that (x 2):8=3:4, find the value of x?
(x 2):8=3:4
(x 2)/8=3/4
4(x 2)=3*8
4x 8 = 24
x=4

5(b)If (x y):(y 9)=2:3, find the value of y by using the result of a
(x y):(y 9)=2:3
(4 y)/(y 9)=2/3
12 3y =2y 18
y=6

8(a)Expand (3x-y)^2
(3x-y)^2
9x^2-6xy+y^2

8(b)Expland (x+3y)^2
(x+3y)^2
=x^2+6xy+9y^2

1.7/5y+3/5y
= 10/5y =2/y
So answer is B

2.x(k-1)=y
k-1=y/x
k=y/x+1
So answer is A

3.A set of data having finite number of values or data points is called Discrete Data.
Number of hours John spent swimming in a week - This is an example of discrete data as swimming period (finite) of John will be specific.

So answer is D

4.4x(8x^2-2x+7)
=32x^3-8x^2+28x

5.a) (x+2):8=3:4
(x+2):8 = 6:8
X+2 = 6
X = 4

b) (x+y):(y+9)=2:3
(4+y): (y+9) = 2:3
(4+y)/ (y+9) =2/3
3(4+y) = 2(y+9)
12+3y = 2y +18
y= 6

6.Is a constant
Let n= 1, term = 3
Let n=2, term= 7
Let n=3, term = 12

Term different between n=1 & n=2 is 5 and term different between n=2 & n=3 is 5, both are number 5

7.(7-x^2-2x^2)-(3x^2-6-x^3)
=7-x^2-2x^2-3x^2+6+x^3
= x^3-6x^2+13

8.a) (3x-y)^2 = 9x^2 -6xy +y^2
b) (x+3y)^2 = x^2 + 6xy +9y^2
c) (3x-y)^2-(x+3y)^2
= 9x^2 -6xy +y^2 – (x^2 + 6xy +9y^2)
= 8x^2 -12xy -8y^2
=Px^2-Qxy-Py^2

So P=8, Q=12