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.
If angle ec is a bisector then angles Bec and ced are the same making them both 4x+1. we know a line segment equals 180°. so if we take the 11x-12 and add it to 2(4x+1) we end up with 19x-10=180. you add 10 to both sides and get 19x=190 then you divide by both sides. you'll end up with x=10. you plug In the 10 with aeb and aec and add them together to get 139°. if you're looking for the equation, it's 15x-11.
other leg = 12 cm
using Pythagoras' identity with x as the side to be found, then
x = √(13² - 5² ) = √(169 - 25 ) =√144 = 12
