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1. I'm having some trouble working out the following maths question:

1a) Given that 3to the power of x = 9 to yhe power of y-1, show that x = 2y -2.

b) solve the simultaneous equations x = 2y-2
xsquared = ysquared + 7
Thanks in advance.
2. 1a) 3^x = 9^y-1
so 3^2(y-1) is the same as that as 3^2 is 9.
= 3^2y-2
so x = 2y-2

b) if x = 2y - 2 you can substitute this into the equation.
so 2y^2 - 8y + 4 = y^2 + 7
use the quadratic formula.
after the beginning steps you should get (8+- root 76)/2
which simplifies to 4+- 3root2.

I think that's correct. Sorry if it isnt
3. (Original post by Kay94)
1a) 3^x = 9^y-1
so 3^2(y-1) is the same as that as 3^2 is 9.
= 3^2y-2
so x = 2y-2

b) if x = 2y - 2 you can substitute this into the equation.
so 2y^2 - 8y + 4 = y^2 + 7
use the quadratic formula.
after the beginning steps you should get (8+- root 76)/2
which simplifies to 4+- 3root2.

I think that's correct. Sorry if it isnt
Thanks for the help on part 1. But when I used the quadratic formula I got 8 +- 10/ 6

...........could you just recheck your answer please and if you still think yours is correct could you explain why.
4. (Original post by Shopaholic94)
I'm having some trouble working out the following maths question:

1a) Given that 3to the power of x = 9 to yhe power of y-1, show that x = 2y -2.

b) solve the simultaneous equations x = 2y-2
xsquared = ysquared + 7
Thanks in advance.

Cancel the

5. (Original post by Shopaholic94)
I'm having some trouble working out the following maths question:

1a) Given that 3to the power of x = 9 to yhe power of y-1, show that x = 2y -2.

b) solve the simultaneous equations x = 2y-2
xsquared = ysquared + 7
Thanks in advance.
For part 2:

So:

This does factorise, no need for quadratic formula:

So, or

Work out from there...
6. (Original post by Dededex)
For part 2:

So:

This does factorise, no need for quadratic formula:

So, or

Work out from there...
Thank you so much!
7. (Original post by Shopaholic94)
Thank you so much!
No problem
8. (Original post by Shopaholic94)
Thanks for the help on part 1. But when I used the quadratic formula I got 8 +- 10/ 6

...........could you just recheck your answer please and if you still think yours is correct could you explain why.
Oh yes, apologies, really stupid mistake that I made there lol. Yeah it is 8+- 10/6. So working it out gives y = 3 and y = -1/3. And then obv substitute that into the original x = 2y - 2 equation to give the values of x = 4 and x = -8/3.

Hope I didn't make any more mistakes there.
9. (Original post by Kay94)
Oh yes, apologies, really stupid mistake that I made there lol. Yeah it is 8+- 10/6. So working it out gives y = 3 and y = -1/3. And then obv substitute that into the original x = 2y - 2 equation to give the values of x = 4 and x = -8/3.

Hope I didn't make any more mistakes there.
Its alright. Thank you anyway!
10. (Original post by Dededex)
..
(Original post by Kay94)
..
Please read the Guide to Posting and in particular what it has to say about posting full solutions.
11. (Original post by DFranklin)
Please read the Guide to Posting and in particular what it has to say about posting full solutions.
Sorry should've read that

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