Math question, can you please help?

Question

Hi,

Okay so I'm doing this big math packet but I'm stuck on this problem.

Graph P(x)=x(x-3)(x+1) Then tell if the graph of y=P(x) is above or belove the x-axis for each of the given set of x-values:

x<-1 -1<x<0 0<x<3 x>3

How do I do this?

I thinkkk the P(x)=x(x-3)(x+1) turns to x3- 2x3-3x

but I don't remember how to graph it, and don't know how to do the rest.

Help please??

Answer 1

x&lt;-1

for these valves   x     x-3     and  x+ 1   all three expression will be -ve

so  graph will fall below x axis

-1&lt;x&lt;0  

for this    x    and  x-3  will be neagative  and  x+1  will be positive   so the product of all expersision will be +ve  

so graph will fall above x-axis

0&lt;x&lt;3

for this   x and  x+1 will be +ve and x-3 will be -ve

so product will be -ve

so graph will fall below x axis

for x&gt;3

all three expersion will be positve so result will be positive so graph will fall above x axis

I thisnk it is sufficient to select a best answer

thank u have a nice day

Answer 2

assume the values of x  for example, x&lt;-1 then assume that the value of x is -2 after assuming those points, substitute them to the equation then graph it :D, let me assume for you.

these are my points:

-2, 0, 1.5, 4

try them :D then you can see if the equation is ABOVE the x axis

PM me or email me ^____^ if u wanna ask some more

is this analytic geometry?

Answer 3

WHOAAA!

Im not that smart.

sorry buddy.  

Answer 4

Okay, i&#039;m only in year seven and even i know that the first section of that question doesn&#039;t make sense. if P=C you need to know what number equals P before you can times it by -3 and plus it by 1.

then is the second part referring to the axis on a grid where you have y+,y-, x+,x- make it clearer.