If it has rational coefients and is a polygon
if a+bi is a root then a-bi is also a root
the roots are -4 and 2+i
so then 2-i must also be a root
if the rots of a poly are r1 and r2 then the factors are
f(x)=(x-r1)(x-r2)
roots are -4 and 2+i and 2-i
f(x)=(x-(-4))(x-(2+i))(x-(2-i))
f(x)=(x+4)(x-2-i)(x-2+i)
expand
f(x)=x³-11x+20
Work out the top subtraction first:
3/9 - 8/12
= 1/3 - 2/3
= 1/3
and the bottom part:-
3/8 * 2 = 6/8 = 3/4
so now we divide -1/3 by 3/4
= -1/3 * 4/3 = -4/9
Answer:
The answer to that is B. 129°
