Could any one help me figure out the last two parts? Thanks

Given the equation of a quadratic function:
[tex]f(x)=x^2-3x-28[/tex]First, we will find the x-intercepts to find the largest x-intercept
So, substitute f = 0, then solve for x as follows:
[tex]\begin{gathered} x^2-3x-28=0 \\ (x-7)(x+4)=0 \\ x-7=0\rightarrow x=7 \\ x+4=0\rightarrow x=-4 \end{gathered}[/tex]So, The largest x-intercept = 7
Second, we will find the y-coordinate of the y-intercept
So, substitute x = 0
[tex]f(x)=(0)^2-3(0)-28=-28[/tex]So, The y-coordinate of the y-intercept = -28