Error in the condition of the problem?

Question

Mathematics

Problem Condition:
Implement the GetMinX method to find a number x such that the curve given by the equation
y(x) = ax^2 + bx + c
takes the minimum value.
The method must accept a non-negative coefficient a, as well as arbitrary coefficients b and c, and, if a solution exists, return the string representation of the desired xx, otherwise, the Impossible string.
Question
Most likely I'm wrong, but still. I decided that here it is necessary to solve a quadratic equation, I began to solve through the discriminant, but the system did not make such a decision. I had to use the hint and it turned out that x = -b / 2a is solved in one step .
Then why is it necessary in the task with ? To confuse what?

Answer 1

c only affects the vertical positioning of the chart.
That is, we increase c , - and the graph rises. In this case, the coordinate of the minimum value (in x ) does not change.