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# 3^3x / 3^(x-5) =3^17 Help! watch

1. You need to solve for x

I got x = 11

The textbook got x = 6 they change the x-5 bit into an x+5, I dont know why :/

Help is appreciated thanks.
2. Since all of these are powers of 3, it's like doing simple powers where, for exampe. x ^ 4 / x ^ 3 = x ^ (4 - 3)

So, on the lhs, subtract the two powers and watch your signs, put it equal to 17 and solve.

I think (I'm guessing because i can't see your working) where you've gone wrong is with the 3x - (x-5) - that negative sign before the bracket will change the sign inside.
3. 387420489 / 3 = 129140163

How tf you got 11 you would have to explain to me,

but its 3^(3x6) = 3^18 = 387420489
3^ (6-5) = 3^1 = 3
3^17 = 129140163
4. (Original post by tomnelson_)
387420489 / 3 = 129140163

How tf you got 11 you would have to explain to me,

but its 3^(3x6) = 3^18 = 387420489
3^ (6-5) = 3^1 = 3
3^17 = 129140163
Urrm you forgot the bit that said "Solve for X" in the desc
5. (Original post by phys981)
Since all of these are powers of 3, it's like doing simple powers where, for exampe. x ^ 4 / x ^ 3 = x ^ (4 - 3)

So, on the lhs, subtract the two powers and watch your signs, put it equal to 17 and solve.

I think (I'm guessing because i can't see your working) where you've gone wrong is with the 3x - (x-5) - that negative sign before the bracket will change the sign inside.
Cheers i see it now thanks
6. (Original post by lollolokjob)
Urrm you forgot the bit that said "Solve for X" in the desc
because its six....

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