How do you graph y=x^2-14x+24?

1 Answer
Jul 15, 2015

You'll have a parabola passing through:
x=0, y=24
x=2, y=0
x=12, y=0
and vertex at x=7, y=-25

Explanation:

This is a Quadratic and its graph will be a Parabola (kind of "U" shaped curve). To plot it you may consider some interesting features of your equation:

1] the coefficient of x^2 is 1>0 so yours will be a "upward" or "happy" parabola (in the shape of a smiling "U");

2] set x=0 into your equation to find the y-intercept:
y=0+0+24
so your parabola will cross the y axis at y=24;

3] set y=0 into your equation to find (if they exists) the x-intercepts(s):
x^2-14x+24=0 solving using the Quadratic Formula you get:
x_(1,2)=(14+-sqrt(196-96))/2==(14+-10)/2=
you get two values:
x_1=24/2=12
x_2=4/2=2
so your parabola crosses the x axis at x=2 and x=12;

4] the vertex; this is a very important point because it characterize the entire graph setting the central point you need to have when plotting a parabola.
Given the equation in general form y=ax^2+bx+c; in your case you have:
a=1
b=-14
c=24
The coordinates of the vertex are then given as:
x_v=-b/(2a)=-(-14)/2=7
y_v=-Delta/(4a)=-(b^2-4ac)/(4a)=-100/4=-25

Finally your graph will look like:
graph{x^2-14x+24 [-83.3, 83.3, -41.64, 41.64]}