What was the first year that the amusement park had more than 12 million visitors?

Answer:The first year that the amusement park had more than 12 million visitors is 2008.Step-by-step explanation:Given:[tex]y=4.2\sqrt{0.28x-1}[/tex]As per the question, the number of visitors must be greater than 12 million.So, [tex]y>12[/tex]Plug in [tex]4.2\sqrt{0.28x-1}[/tex] for [tex]y[/tex] and solve for [tex]x[/tex].[tex]4.2\sqrt{0.28x-1}>12[/tex][tex]\sqrt{0.28x-1}>\frac{12}{4.2}\\0.28x-1>(\frac{12}{4.2}) ^{2} \\0.28x>8.16+1\\x>\frac{9.16}{0.28} \\x>32.7\\[/tex]Therefore, least value of [tex]x[/tex] for which the number of visitors are more than 12 million is [tex]x=33[/tex].Since, [tex]x[/tex] is measured after 1975.Therefore, the first year that the amusement park had more than 12 million visitors is [tex]1975+x=1975+33=2008[/tex].