Zeros of a Fuction: Finding a stationary point

The following function has been graphed below:

$f(x)=-x^2+5x+6$

Calculate points A and B.

$(-1,0),(6,0)$

The following function has been graphed below:

$f(x)=x^2-6x+8$

Calculate points A and B.

$(2,0),(4,0)$

The following function has been graphed below:

$f(x)=x^2-8x+16$

Calculate point A.

$(0,16)$

The following function has been graphed below:

$f(x)=x^2-6x+5$

Calculate points A and B.

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$(1,0),(5,0)$

The following function has been graphed below:

$f(x)=x^2-8x+16$

Calculate point C.

$(4,0)$

The following function has been graphed below:

$f(x)=x^2-6x$

Calculate points A and B.

$(6,0),\lparen0,0)$

The following function has been graphed below:

$f(x)=x^2-3x-4$

Calculate points A and B.

$A(-1,0),B(4,0)$

The following function has been graphed below:

$f(x)=x^2-6x+5$

Calculate point C.

$(0,5)$

The following function has been graphed below:

$f(x)=x^2-6x+8$

Calculate point C.

$(0,8)$