I have a question that asks "By substituting $x=10$ in the equation, find...". This is the formula in the question, which forms a parabola (representing the path of a ball):
$$y=-0.05x^2+x+1.8$$
However, if I attempt to substitute $x=10$, as stated in the question, I get a straight line. For example:
$$y=-0.05\cdot10^2+10+1.8$$ or $$y=-0.5^2+11.8$$
Based on the follow-up questions, I don't believe a straight line is the intended result. What am I doing wrong when substituting $x=10$?