What is the value of c so that x2 - 11x+c is a perfect-square trinomial?
To make x^2 - 11x + c a perfect square trinomial, we need to find the value of c such that the trinomial can be factored as (x - a)^2 for some value of a.
If we expand (x - a)^2, we get x^2 - 2ax + a^2. Comparing this to x^2 - 11x + c, we can see that -2a = -11 or a = 11/2.
Therefore, c = (11/2)^2 = 121/4.
So, the value of c is 121/4.