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Can anyone help with these two questions

Screenshot_20200914_165051-compressed.jpg.jpeg

2. find x as a fraction of 2x^½=9/8
Original post by EDX_brutality

2. find x as a fraction of 2x^½=9/8

But you're not after a value of x here.

You are after the values of a,b.

You need to construct two equations in a,b and solve them simultaneously.

E.g. from the first relation, we have x2a=x8bx^{2a} = x^{8b} therefore we must have 2a=8b2a = 8b.

Likewise with the second equality for another equation, hence solve for a,b.
Original post by RDKGames
But you're not after a value of x here.


I think 2. is a separate (and not terribly well laid out) question.
Original post by DFranklin
I think 2. is a separate (and not terribly well laid out) question.

Yh, they are separate questions lol
Reply 4
Avatar for AshwinUK
AshwinUK
3
1) Laws of Indices play a large part in this question.

Start by expanding brackets, remembering that (xm ) n = xmn
This should provide you with a value of a in terms of b, since x2a = x8b , thus 2a = 8b , a = 4b
Sub this into the second equation and solve (similar to a simultaneous equation)

Key points to help: sqrt(x) = x1/2
x3 divided by xb
= x3-b
2) Similar skills, remember sqrt(x) = x1/2 From that you should be able to square both sides and solve x as a fraction. Remember (9/8)2 = 81/64
(edited 3 years ago)
Original post by DFranklin
I think 2. is a separate (and not terribly well laid out) question.

Yeah and I definitely misread it as "found" rather than "find" hence thinking they tried to solve for x and ended up at that stage.
for the first problem, I think this step usually opens the path for the rest of the solution

surd_2.jpg
More generally, for all surd problems involving nth root, the following realization helps a lot

surd_3.jpg

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