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19 votes
Work out 5^-2 x cube root 8

User Torrho
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1 Answer

20 votes
20 votes

Answer:

0.08

Explanation:

5 ^-2 * cube root of 8

first of all, let us solve 5^-2

using the law of indices;

a^-2 = 1 / a ^2

following this law, we have;

5^-2 = 1 / 5^2

we know that 5^2 = 25

therefore,

5^-2 = 1 / 25

now, let is continue by solving the cube root of 8

now, there are three ways of solving this;

we could just simply think of any number that when multiplies itself three times times, it gives 8, or we could just simply use a calculator

regardless of what we use, we have to end up with the number 2 as the answer

leading is to our conclusion.

from all our solution, we have reduced our question to;

1 / 25 ( which is 5^-2) * 2 ( which is the cube root of 8 )

= 1 / 25 * 2 / 1

note that 2 is the same as 2 / 1. We put it like this when we want to carry out an operation on an integer ( e.g. 2) and and a fraction ( e.g. 1 / 25 )

so,

1 / 25 * 2 / 1 =

2 / 25 ( the two multiplies the 1 in 1 / 25 and the 25 multiplies the 1 in 2 / 1)

leaving our answer in decimal, we have;

0.08

hope this helps,

thanks!!!

User Leeann
by
3.1k points