Question

What is the vertex of the graph of this function? V = - (x - 3)(x+1) A. (-1,0) B. (1,-4) C. (1,-3) D. (1.4)

Answer 1

Given equation is,

`v=-(x-3)(x+1)`
`\begin{gathered} v=-(x-3)(x+1) \\ v=(-x+3)(x+1) \\ v=-x^2-x+3x+3 \\ v=-x^2+2x+3 \end{gathered}`

Now, let us solve the above equation.

`\begin{gathered} v=-x^2+2x+3 \\ v=-(x^2-2x-3) \\ v=-(x^2-2x+(-1)-(-1)-3) \\ v=-((x-1)^2-(-1)^2-3) \\ v=-((x-1)^2-4 \\ v=-(x-1)^2+4 \end{gathered}`

the vertex is at (1,4)