1) Expand (x + 5)<sup>3</sup>
Either apply the Binomial Theorem, or just multiply things out.
. . . . .(x + 5)<sup>3</sup> = (x + 5)(x + 5)(x + 5)
. . . . .(x<sup>2</sup> + 10x + 25)(x + 5) = ...?
2) Simplify (s/2) - ??
Is the "radical sign" a square root? A cube root? Some other root? Is the radical subtracted from s/2, as you have posted, or is it part of the denominator?
3) 2x<sup>2</sup> - x - (23/3x<sup>2</sup>) - x - (2/4x<sup>2</sup>) + 16x + (7/3x<sup>2</sup>) + 11x + 6
I will guess that the instructions are to simplify...? If you posted correctly, you have three fractions with denominators of 3x<sup>2</sup>, 2x<sup>2</sup> (after reducing the 2-over-4 bit), and 3x<sup>2</sup>. Convert these fractions to the common denominator of 6x<sup>2</sup>, and add. The other terms can just be combined as usual.
(If you meant something other than what you posted, please reply using grouping symbols to clarify your meaning.)
Eliz.
