1. The UV index on a sunny day can be modelled by the function y= -0.15(x-13)^2+7.6 , where x represents the time of day on a 24-h clock and f(x) represents the UV index. At what time(s) was the UV index 7?

Question

2. Determine if each system has one, two, or no solutions. (Show your work - 3 marks each)
a)y=2x^2-2x+1 and 3x-5
b)y=x^2+3x-16 and y= -x^2-8x-18

Answer 1

#1 well just solve

-0.15(x-13)^2+7.6 = 7
just the usual quadratic stuff.

#2
The discriminant gives this information.
b^2-4ac:
<0 no roots
=0 1 root
>0 two roots

Answer 2

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