Help maths

Alevelhelp.1

15

Hi this is a easy q but I forgot…

And is this rearranging fine?

(edited 11 months ago)

Reply 1

mqb2766

21

If x=1, then the original expression is 3^4 so ...

Reply 2

Alevelhelp.1

OP

15

Original post by mqb2766

If x=1, then the original expression is 3^4 so ...

Multiply right

Reply 3

mqb2766

21

Yes. Exponent laws are in
https://www.mathsisfun.com/algebra/exponent-laws.html
and multiplying terms means adding exponents when the bases are the same, and in the edited picture subtracting exponents is equivalent to division.

But get in the habit of trying simple numbers to check in these cases.

(edited 11 months ago)

Reply 4

Alevelhelp.1

OP

15

Original post by mqb2766

Yes. Exponent laws are in
https://www.mathsisfun.com/algebra/exponent-laws.html
and multiplying terms means adding exponents when the bases are the same, and in the edited picture subtracting exponents is equivalent to division.

But get in the habit of trying simple numbers to check in these cases.

Thanks!
You know for the second pic I sent…

it’s correct what I wrote right?
or would it be 3^(2/x)

Reply 5

davros

16

Original post by Alevelhelp.1

Thanks!
You know for the second pic I sent…

it’s correct what I wrote right?
or would it be 3^(2/x)

what you've written is correct -

3^{2-x} = \dfrac{3^2}{3^x}

3^{2/x}

is the same as

\sqrt[x]{3^2}

Reply 6

mqb2766

21

The second pic is right. Im assuming you read the mathsisfun link/your textbook? So long winded ...
3^(2-x) = 3^2 * 3^(-x) = 3^2 * (1/3^x) = 3^2/3^x
Using the exponent multiplication rule
3^(2/x) = (3^2)^(1/x)

Or again try x=1, especially when youre unsure about simple rules.

(edited 11 months ago)

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