There are 5 x 10 = 50 different outcomes.
Of them only 3x10, 4x10, 4x9, 4x8, 5x10, 5x9, 5x8, 5x7 and 5x6 are greater or equal than 30. Those are 9 possibilities.
Then 50 - 9 = 41 are the possibilities that the product of the two numbers is less than 30.
The probalility, then, is 41/50 = 0.82
The segment of length x bisects the chord of length 19.2.
The diameter is 24, so the radius is 12.
You have a right triangle with hypotenuse 12, and one leg 19.2/2 = 9.6
9.6^2 + x^2 = 12^2
92.16 + x^2 = 144
x^2 = 51.84
x = 7.2
I suppose you mean

Differentiate one term at a time.
Rewrite the first term as

Then the product rule says

Then with the power and chain rules,

Simplify this a bit by factoring out
:

For the second term, recall that

Then by the chain rule,

So we have

and we can simplify this by factoring out
to end up with
