Can someone help me solve this? I don't know what I am doing wrong. I need to complete the square to find the vertex. Please show me how you do it. f(x) = −x2 + 2x − 3

Mathematics · High School · Tue Nov 03 2020

Answered on

Given : 

f(x) = −x2 + 2x − 3

Now, we have to solve it by completing square. 

We can write given equation as

x²-2x=3

x²-2x+1=3+1

(x-1)²=4              {by (a+b)^2 = a^2 -2ab + b^2}

now, taking square root of both sides, we get

x-1=±2

Taking positive sign

x= 1+2

x=3

Now, taking negative sign

x= 1-2

x=-1

 

Hence, the vertex are (3, -1)