To write 4 as a time you write 4:00, Then the word after means to add 23 minutes to the 4 so we have 4:23
Not sure why such an old question is showing up on my feed...
Anyway, let

and

. Then we want to find the exact value of

.
Use the angle difference identity:

and right away we find

. By the Pythagorean theorem, we also find

. (Actually, this could potentially be negative, but let's assume all angles are in the first quadrant for convenience.)
Meanwhile, if

, then (by Pythagorean theorem)

, so

. And from this,

.
So,
3 x 1/8 bottom left. The third one
Both 15 and 20 can be divided evenly by 5, so 5 is the greatest common monomial: 5(3x^2 + 4x) or 5x(3x + 4)