Who could help me please and thank you

Only answer if you know how to do the equation

Bring the fraction a/a-4 to a denominator of 16-a^2

Aroulette wheel has 38 slots in which the ball can land. two of the slots are green, 18 are red, and 18 are black. the ball is equally likely to land in any slot. the roulette wheel is going to be spun twice, and the outcomes of the two spins are independent.the probability that it lands one time on red and another time on black in any order is(a) 0.5 (b) 0.25 (c) 0.4488 (d) 0.2244

My hour hand points between the 8 and the 9 in 35 minutes it will be the next hour. what time is it ?