Answer
No inflection point.
Work Step by Step
Step 1. Take the derivatives of the function to get $y'=2ax+b$ and $y''=2a, a\ne0$
Step 2. If $a\gt0$, the function will be concave up, while if $a\lt0$, the function will be concave down.
Step 3. The quadratic function does not have an inflection point where the concavity can change across the point.
