Answer:
a) y = 
b) x = 4
Step-by-step explanation:
a) 
3y + 2 = 20y - 5
2 = 20y - 3y - 5
2 = 17y - 5
2 + 5 = 17y
7 = 17y
y = 
b) x² + 5 = 21
x² = 21 - 5
x² = 16
x = √16
x = 4
90% of 100 = 0.9 x 100 = 90
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Answer: The visitor can see 90 ships.
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Angle t would be equal to cos(60 degrees) which has coordinates (1/2,sqrt3/2) so that answer is 1/2