3/8 of a lap is 1/32 of the entire race.
x - the number of laps in the race

There were 12 laps in the race.
In a rhombus, all sides are equal:
5x = 15
and x = 15/5 = 3
(you could have done the same thing with the other side: 5x = 4x +3)
hi,
you must replace x by the number between parenthese.
I show you with the first one and let you do the second one
p(x) = 11x^5 -11x^4 - 5x^2 +15x-8
p(-4) = 11 (-4)^5 - 11 (-4)^4 -5(-4)² +15(-4) -8
p(-4) = 11 ( -1024- 256) - 5*16 -60-8
p(-4) = 11 ( -1280) -80-60-8
p(-4) = - 14080 - 148
p(-4) = - 14 228