How do you graph x= -3(y-5)^2 +2?

1 Answer
Aug 9, 2015

The graph is an "n" shape . From the equations alone, we can tell for sure that this is a quadratic equation (either "u" or "n" shaped).

Explanation:

Expand the equation to get;
x=-3y^2+30y-73

  • Find turning points and determine if they are maximum points or minimum points.
  • Next, find points of intersection on the vertical and horizontal axis.

Finding turning points (df(x)/dx=0 );

dx/dy=-6y+30 where dx/dy=0

Hence, y=5. When y=5, x=2
The turning point is at coordinate (5,2) and it is a maximum point since the graph is an "n" shape. You can tell the "n" shape if the coefficient for the y^2 is a negative .

Finding intersections :

Vertical axis ;
Let y=0,
x-3(0-5)^2+2.
x=-73

Horizontal axis :
Use (-b+-sqrt(b^2-4ac))/(2a).

You should get something like this (scroll on the graph to get a better view):

PS: Feel free to ask away any questions.

** graph{-3x^2+30x-73 [-11.25, 11.25, -5.625, 5.625]} ** :