Answer:
1. 
2. not completely sure but i think its 
3.x
=
2
i
√
5
,
−
2
i
√
5
4.x
=
−
9
±
√
73
/2
5. Im not sure...
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Of 85% of cars sold where not black then 100-85% where black = 15%
let the number of cars sold be y
then 15%*y=300
y= 300 divided by 15%
= (300*100)/15
=2000
therefore 2000 cars were sold
189 because 20.7 rounds to 21 and 9.18 rounds to 9
21 * 9 = 189
X=8 & z=66
because vertical angles are congruent