A parabola with equation  $y = x^2 + bx + c$ passes through the points $(2,3)$ and $(4,3)$. What is $c$?
I know that a parabola is a quadratic function of the form $y = ax^2 + bx + c$, where $a$, $b$, and $c$ are constants. Since the parabola passes through the points $(2,3)$ and $(4,3)$, I can plug in those values of $x$ and $y$ into the equation and get two equations with two unknowns: $b$ and $c$. The equations are: $3 = 4 + 2b + c$ and $3 = 16 + 4b + c$. I can subtract the first equation from the second to eliminate $c$ and get: $0 = 12 + 2b$. Solving for $b$, I get: $b = -6$. Now that I know $b$, I can plug it back into either equation to find $c$. I'll use the first one: $3 = 4 - 12 + c$. Simplifying, I get: $c = 11$. 