posted by Tonya on .
How can I tell what direction this parabola open up
We just started this in class today do I need to change this into another format
The leading coefficient tells the story.
The leading coefficient of a polynomial is the coefficient (number) associated with the variable of the highest power, in this case, x².
If the leading coefficient (-2) is negative, it is concave down, i.e. it opens downwards. If the leading coefficient is positive, it is concave up.
An easy way to remember is the concavity follows the same direction along the y-axis as the leading coefficient. Positive => upwards, negative => downwards.