Question 110761
1. Factor
-9w+9u-tw-+ut
-9(w-u)+t(w-u)
(w-u)(t-9)
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2. Factor
6b^4/5c^4d^2/3ab^3/15c^2d
Invert the denominator and multiply:

[6b^4 / 5c^4d^2] * [15c^2d / 3ab^3]

Cancel factors tht are comon a numerator and a denominator 
like 3,5,c^2, b^3, d

=  [ 6b / c^2d ] * [1/a]

=  [6b/ac^2d]
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3. xsqrt(80xw^2) + 5wsqrt(5x^3)
  
= 4xw sqrt(5x) + 5xw sqrt(5x)

= 9xw sqrt(5x)

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Cheers,
Stan H.