MC question

1.
x^4+6x^2-7=0
(x^2+7)(x^2-1)=0
x^2+7=0 or x^2=1

The answer is D

2.
x^6 + 9x^3 + 8 = 0
(x^3+8)(x^3+1)=0
x=-2 or -1
The answer is C

3.
3x^2-2x-1=0
(3x+1)(x-1)=0
x=1
The answer is A

4.The figure shows the graphs of y = ax2 + bx + c, y = mx + d and y = nx + e. Determine the number of real root(s) of ax2 + (b-n)x + (c-e) = 0.
A.No real roots
B.1
C.2
D.3

Do not have enough information

5.Which of the following equations CANNOT be solved by using the following graphs?
A.ax2 + (b – m)x + (c – d) = 0
B.ax2 + (b + n)x + (c – e) = 0
C.(m – n)x + (d – e) = 0
D.–ax2 – (b – m)x + (d – c) = 0

Do not have enough information

6.The following figure shows the graphs of y = ax2 + bx + c and y = mx + d. Which of the following MUST be true?
A.a2 < 4(b – m)
B.a2 > 4(b – m)
C.(b – m)2 < 4a(c – d)
D.(b – m)2 > 4a(c – d)

Do not have enough information


7.
y=2x^2 and want to solve 4x^2 + 3x – 4 = 0
Since 4x^2 + 3x – 4 = 0
2x^2 + (3/2)x – 2 = 0
2x^2=(-3/2)x+2

So the straight line is (-3/2)x+2

8.Solve the simultaneous equations
A.(1.5, 3), (-4, -8)
B.(-1.5, -3), (4, 8)
C.(2, 4), (-3, -6)
D.(-2, -4), (3, 6)

Do not have enough information

9.Given that the simultaneous equations have two distinct real roots. Which of the following MUST be true?
A.k > -1
B.k < -1
C.k > 1
D.k < 1

Do not have enough information

10.
Using trial and error x=-1 is a root
x^3 – 3x^2 + 4 = 0
(x+1)(x^2-4x+4)=0 = 0

So x=-1 or 2
The answer is C

Please give more information for other questions

題目可否清楚些
x3=x既3次方?
第3題的答案
A.x = 1
B.x = or 1
C.x = or 1
D.x = , or 1
BCD另外果個=咩
問題係
3x - 2 - 1 = 0
定係
3既X次方-2-1=0

2008-12-23 13:08:54 補充：
後面幾題直頭好多都冇左D野...