At which points will the graphs of y = 2x^2 and y = 6x intersect?

Question

At which points will the graphs of y = 2x^2 and y = 6x intersect?

 

A. (0.0) and (3, 18)

B. (3, 18) and (-3, 18)

C. (0, 0) and (3, 6)

D. (3, 6) and (-3, 6)

Answer 1

The graphs of y = 2x^2 and y = 6x when they have the same x and y values.

 

Let's find the x value first (using the elimination method):

    y = 2x^2

    y = 6x

  -----------   (subtract equations)

   0 = 2x^2 - 6x

   0 = 2x(x-3)         (factor)

This will be true when x=0 and x=3.  The values of y [note:6x] will be 0 and 18.

So, the points are (0,0) and (3,18)

Answer 2

There are different ways that you can solve this problem...

 

1st --> set the equations equal to each other and solve for the x and then plug that x into each equation and get the outcome and make sure they're the same (6x=2x^2 --> x=?)

 

2nd--> plug in x values for each and see if you get the same output. (Make a t chart)

 

x | y 

0 | ?

1 | ?

2 | ?

3 | ?

4 | ?

 

3rd--> you can plug in the x's and y's from the solutions of the multiple choice problems they gave you and eliminate answers to find right one.