Which of the quadratic functions has the narrowest graph?

y = −10x2

y = −0.9x2

y = 9x2

Explanation:

The equation y = ax^2+bx+c has the value of 'a' determine how wide or narrow the graph is. The closer 'a' is to zero, then the wider it gets; while the further 'a' is from 0, the narrower it gets.

What we need to do is look for equations in which the 'a' value is furthest from 0. In this case, it's with y = -10x^2 since a = -10 is furthest from zero compared to a = -0.9 and a = 9. Set up a number line to help see this. You can also use absolute values to get the job as well.

Therefore, y = -10x^2 has the most narrowest graph.