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another Maths A level question

w=2^m

Select the correct expression for
w^3
I know its simple but i seem to be getting the wrong answer
Can you post your working so far?
w=2^m and u want w^3 so u replace the w in the equation and get (2^m)^3. Expand those brackets and u should get your answer.
Reply 3
(2m)^3=2m^3?
w=2mw=2^{m}

w3=?w^{3}=?

Do you understand the Laws of Indices?
Original post by laila777
(2m)^3=2m^3?

you need to cube 2 aswell
Reply 6
[quote="mathstutor24;89319148"]w=2mw=2^{m}

w3=?[/latex[br][br]DoyouunderstandtheLawsofIndices?w^{3}=?[/latex[br][br]Do you understand the Laws of Indices?
8m^3? yes i do
w3=(2m)3 w3=2(m×3) w3=(23)m w3=?w^{3}=(2^{m})^{3}\\\\\therefore \ w^{3}=2^{(m \times 3)}\\\\\therefore \ w^{3}=(2^{3})^{m}\\\\\therefore \ w^{3}=?
(edited 3 years ago)
Reply 8
Original post by mathstutor24
w3=(2m)3 w3=2(m×3) w3=(23)m w3=8mw^{3}=(2^{m})^{3}\\\\\therefore \ w^{3}=2^{(m \times 3)}\\\\\therefore \ w^{3}=(2^{3})^{m}\\\\\therefore \ w^{3}=8^{m}

thanks. I have another question.....
Reply 9
y=5^x
Select the correct expression for 25y
Original post by laila777
y=5^x
Select the correct expression for 25y

What have you done so far?

if y=5xthen 5y=?if\ y=5^{x}\\\\then\ 5y=?
I'm not sure that you fully understand the laws of indices. It's okay if you don't, but you may like to check out this page first. Have a go and then post your working/answer to check.
Reply 12
Original post by mathstutor24
What have you done so far?

if y=5xthen 5y=?if\ y=5^{x}\\\\then\ 5y=?

its not 5y is 25 y
I am familiar now with the laws of indicies
Reply 13
Original post by laila777
its not 5y is 25 y
I am familiar now with the laws of indicies

I think @mathstutor24 was trying to get you there in stages.

If you know that y=5xy = 5^x

then what is 5y=5×5x5y = 5 \times 5^x in index form?

And therefore what is 25y=5×5×y25y = 5 \times 5 \times y in index form?
Original post by davros
I think @mathstutor24 was trying to get you there in stages.

If you know that y=5xy = 5^x

then what is 5y=5×5x5y = 5 \times 5^x in index form?

And therefore what is 25y=5×5×y25y = 5 \times 5 \times y in index form?

Thanks @davros :smile:
No it would be 2^3m.w=2^mw^3(2^m)^32^3m

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