Question 57988
The y-intercept is defined as the value of the function when x=0 (x=0 means you are on the y-axis, look at the graph and you should see why.)

So, just plug in 0 for x and read the answer:
{{{y=3(0)^2-18(0)+15}}}. 
So the y-intercept is {{{highlight(15)}}}.

{{{graph(300,200,-2,8,-30,30,3x^2-18x+15)}}}