How do we know if a function is a parabola like for instance, this one x^2 + x?

There is an easy way to tell whether the graph of a quadratic function opens upward or downward: if the leading coefficient is greater than zero, the parabola opens upward, and if the leading coefficient is less than zero, the parabola opens downward.

the correct answer is C M angle q s t is equal to 160 degree