Answer:
The answer is 1.21.
Step-by-step explanation:
The hundredth digit in 1.208 is 0, so you have to look at the number after that to either round 0 up or down. The number after 0 is 8. Since 8 is bigger than 5, you round 0 up by 1.
I hope this was clear!
Maybe you should work on starting you're sentences.
The x coordinate of the vertex will be the average of the two zeros, here -3 and 5, so x=(-3+5)/2 = 1, f(1)=(1+3)(1-5) = -16.
Answer: (1, -16)
Let's do it some other ways. How about completing the square to turn f in to vertex form?
f(x) = (x+3)(x-5) = x² - 2x - 15 = (x² - 2x + 1) - 1 - 15 = (x-1)² - 16
and now we can read off (1, -16) as the vertex.
The other method is the vertex is x= - b/2a = - (-2)/2(1) = 1.
Three methods, same answer. Good.