# Plot the graph of y = 0.01x^2 - 0.15x

durbanville | Certified Educator

In order to draw the above conclusions, establish values for x and y such that specific points can be "plotted."

The easiest way would be to

1. Find x when y = 0

`y=0.01x^2 - 0.15x`  :

`therefore 0 = x(0.01x - 0.15)`

`therefore x= 0 and (0.01x - 0.15) = 0`

`therefore 0.01x= 0.15`

`therefore x = 0.15/ 0.01`

`therefore x = 15`

`(0;0)` You can see that the graph passes through the origin which is the point at which both x and y = 0

`(15; 0)`

To find the minimum (this is a positive graph so will have a minimum. A negative graph would have a positive) use the formula:

`x=(-b)/(2a)`  where b= 0.15 and a = 0.01 (from original equation)

`therefore x= (-(- 0.15))/(2(0.01))` Note how the negative symbols cancel each other out

`therefore x= 7.5` Now find y at the same point (using the original equation):

`y= 0.01 (7.5)^2 - 0.15(7.5)`

`y= - 0.5625` `or - 5/8`

(7.5; -5/8)

Now the graph shown above can be plotted using these three points.

(0;0) ; (7.5; - 5/8)  ; (15; 0)

justaguide | Certified Educator

The graph of y = 0.01*x^2 - 0.15*x has to be drawn.

As the highest power of x in 0.01*x^2 - 0.15*x is 2, the graph is not a straight line; it is a parabola.

The required graph is:

mmags3 | Student

Just a note to say a big thank-you

for the replys it is much clearer now.

Now I can go ahead with it and I also

understand it.

mmags3 | Student

The graph of y = 0.01*x^2 - 0.15*x has to be drawn.

As the highest power of x in 0.01*x^2 - 0.15*x is 2, the graph is not a straight line; it is a parabola.

The required graph is: