Chapter 5 Polynomials and Polynomial Functions - 5.7 Apply the Fundamental Theorem of Algebra - 5.7 Exercises - Mixed Review - Page 386: 71

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The intercept form of a quadratic function is: $$y=a(x-p)(x-q)$$ where $a=1\\p=2\\q=9$ The x-intercepts occur at: $(2,0);(9,0)$ The x-coordinate of the vertex is: $x=\frac{p+q}{2}=\frac{2+9}{2}=\frac{11}{2}=5.5$ Find the y-coordinate: $y=(5.5-2)(5.5-9)=3.5(-3.5)=-12.25$ Hence, the vertex is $(5.5,-12.25)$ The axis of symmetry is $x=5.5$