+0  
 
0
102
3
avatar

At how many points do the graph of the equations y = x^3 and y = x^2 + 4x intersect?

 Nov 2, 2019
 #1
avatar+2833 
+2

Substitute y

 

So now you have:

 

x3=x2+4x

 

0 = x- x- 4x

 

This is a polynomial with a degree of 3, therefore it must have 3 solutions.

 

 

If it has 3 solutions, it has 3 intersections in the graph.

 Nov 2, 2019
 #3
avatar+2833 
+1

Sorry, I tried to edit my answer, but Web2.0 didn't is glitching or something. I can't publish my answer, it just reverts back.

 

Just look at EP's answer, that is the correct method.

CalculatorUser  Nov 2, 2019
 #2
avatar+21753 
0

x^3 =x^2 +4x

x(x^2-x-4) = 0

 

x = 0 , 1/2+ - sqrt(17)/2

 

Three intercepts

 Nov 2, 2019

23 Online Users