KK's Questions Volume3 (1 Viewer)

[KimmorleyKiller]

 |x-3|>2|x+1|

x+1 / x-2 greater/equal to 0

expand and simplify root2 (3root5 - 2root2)

solve 3x / x+1 = 2/3

solve 2x^2-3x-1=0 (3 sig figures)

a+b/5a-20ab^2  divided by  a^2+2ab+b^2/3-6b

Simplify X+1 / 5 divided by x^2-2x-3 / 10

I think i can about 4 of them? lol

cheers guys

 

[_ShiFTy_]

1)

|x-3| > 2|x+1|

When x > 3
x-3 > 2x+2
x < -5 (N/A)

When -1 < x < 3
-(x-3) > 2x+2
-x+3 > 2x+2
3x < 1
x < 1/3

When x < -1
-(x-3) > -2(x+1)
-x+3 > -2x-2
x > -5

-5 < x < 1/3

2)

x+1  > 0
x-2

LHS will be positive, when top and bottom are both positive or both negative
x+1 >0 ... x > -1
x-2 >0 ... x > 2

x+1 < 0 ... x < -1
x-2 < 0 ... x < 2

Therefore x < -1 and x > 2

3)

root2 (3root5 - 2root2)

3root10 - 4

4)

3x   = 2
x+1    3

9x = 2x + 2
7x = 2
x = 2/7

5)

2x^2 -3x - 1 = 0

Use quadratic forumula:

3± Root (9 - 4(2)(-1))
4

Just basic arithmetic from here...

6)

a+b/5a-20ab^2  divided by  a^2+2ab+b^2/3-6b

a+b X 3-6b
5a-20ab^2 a^2+2ab+b^2

a+b X 3(1-2b)
5a(1-4b^2) (a+b)^2

U]1[/U] X 3(1-2b)
5a(1+2b)(1-2b) a+b

1 X 3
5a(1+2b) a+b

3
5a(1+2b)(a+b)

7)

x+1 / 5 divided by x^2-2x-3 / 10

x+1 X 10
5 x^2-2x-3

x+1 X 2
(x+1)(x-3)

2
x-3


To be honest, if you cant do these types of questions without any or much trouble, i dont think 3U is for you


If there are any mistakes in some of my working out...typing out answers is very difficult