Answer:
[tex]y= \frac12 x^2 -2x +\frac32[/tex]
Step-by-step explanation:
From the two zeroes, you can tell that the polynomial factors as [tex]y= A(x-1)(x-3)[/tex]. You have still one degree of freedom (determining how wide the parabola is. You can determine it with the other condition:
[tex]4 = A(5-1)(5-3) \rightarrow 4= A(4)(2) \rightarrow A= \frac12[/tex]
Your function is [tex]y= \frac12 (x-1)(x-3) = \frac12 x^2 -2x +\frac32[/tex]