# Thread: Help Understanding Math Concepts [URGENT]

1. ## Help Understanding Math Concepts [URGENT]

There are some problems I dont know how to work out that I need to understand for tommorows test. If you could just solve them for me with abit of explaining, that would be awesome.

1. x^(1/2) - 3x^(1/3) = 3x^(1/6) - 9

2. 4(x+1)^(1/2) - 5(x+1)^(3/2) + (x+1)^(5/2) = 0

3. If a = [(b^2)/(c^3)] * k, how is values of a changed when values of b + c are halved.

4. If 3x - x^2 > 2 and y^2 + y < 2, find restriction on product xy.

THANK YOU SO MUCH FOR ANSWERING (If you did). Ill continue to try to solve these on my own, but I have been going for hours on them already.

2. I'll give you a start on the first three:

1: Put $\displaystyle z = x^{1/6}$ and then you'll have a cubic in $\displaystyle z$ which factorises easily.

2: Similar technique, this time put $\displaystyle z = (x+1)^{1/2}$ and see what happens.

3: Substitute b/2 for b and c/2 for c in the given equation and see what happens.

3. Okay, I have another one. Let graphs of y = x^2 and y = a - x^2 intersect at points P and Q. If a>0 and length of PQ is equal to 6, what is value of a?