Answer:
13u√2u
Explanation:
Remark
Removing factors from under the square root sign means factoring the numbers into prime factors. If there are an even number of equal prime factors, take one out and throw one away for all the primes that are the same. An odd number of factors always leaves 1 under the root sign.
For example
u^3 = u * u * u
One of the u's will be left behind. Of the two others, one will be discarded and one will be taken outside the root sign.
√u^3 = √(u * u * u) = u√u
- one u taken out.
- 1 u left behind
- 1 u discarded.
Question Breakdown
- 8√72u^3 = 8√2*2*2*3*3 u^3 = 8* 2*3 * u * √2u = 48u*√2u
- 7√128u^3 = 7√(2*2*2*2*2*2*2 u^3) = 7*2*2*2 √2u = 56u√2u
- 3u*√98u = 3u * √(7*7 * 2*u) = 21u√2u
Answer
48u√2u - 56√2u + 21u√2u
13u√2u