Answer:
Step-by-step explanation:
First, look at the graph to determine whether it opens down or up, which in this case is <em>down</em>, so you insert a negative in front of the expression. Next, locate your <em>x-intercepts</em> [<em>zeros</em> (where the graph insects the x-axis)]. You will see that the graph intersects ![\displaystyle [-2, 0]](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5B-2%2C%200%5D)
and ![\displaystyle [4, 0],](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5B4%2C%200%5D%2C)
so what you do is insert the zeros' OPPOCITES into the equation because according to the vertex equation, ![\displaystyle y = A[x - h]^2 + k,](https://tex.z-dn.net/?f=%5Cdisplaystyle%20y%20%3D%20A%5Bx%20-%20h%5D%5E2%20%2B%20k%2C)
that negative in front of 
gives you the OPPOCITE outcome, so be careful.
I am joyous to assist you at any time.
Given : tan 235 = 2 tan 20 + tan 215
To Find : prove that
Solution:
tan 235 = 2 tan 20 + tan 215
Tan x = Tan (180 + x)
tan 235 = tan ( 180 + 55) = tan55
tan 215 = tan (180 + 35) = tan 35
=> tan 55 = 2tan 20 + tan 35
55 = 20 + 35
=> 20 = 55 - 35
taking Tan both sides
=> Tan 20 = Tan ( 55 - 35)
=> Tan 20 = (Tan55 - Tan35) /(1 + Tan55 . Tan35)
Tan35 = Cot55 = 1/tan55 => Tan55 . Tan35 =1
=> Tan 20 = (Tan 55 - Tan 35) /(1 + 1)
=> Tan 20 = (Tan 55 - Tan 35) /2
=> 2 Tan 20 = Tan 55 - Tan 35
=> 2 Tan 20 + Tan 35 = Tan 55
=> tan 55 = 2tan 20 + tan 35
=> tan 235 = 2tan 20 + tan 215
QED
Hence Proved
Answer:
(3,-21)
Step-by-step explanation:
