To find the x-intercepts of the graph of ##y=x^2-11x+18## substitute 0 for y and solve for x.

##0=x^2-11x+18##

Now factor the quadratic expression on the right.

##0=(x-2)(x-9)##

and set each factor equal to 0 and solve.

##(x-2)=0## or ##(x-9)=0## ##=>x=2## or ##x=9##

The x-intercepts of any function ##y = f(x)## are found

by setting ##f(x)=0## since the y-coordinate of any point on the

x-axis is zero.

See image below.