We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive pseudonymised information about your use of our website. cookie policy and privacy policy.
 
+0  
 
0
206
5
avatar

Find all values of x such that x(x+7.5)>38.5 . Answer with interval notation.

 Nov 30, 2018
 #1
avatar+18965 
+2

Expand to x^2+7.5x - 38.5 > 0    Use quadratic formula to find x = -11  and 3.5

 

These are the zeros of a normally upright parabola.....so x outside of these numbers, the fxn would be > 0

     BETWEEN ( & including the values) the values of the function are zero or negative

 

so          -11 >x>3.5

 Nov 30, 2018
edited by ElectricPavlov  Nov 30, 2018
 #4
avatar+805 
0

You are right but it should be in interval notation.

CoolStuffYT  Dec 1, 2018
 #2
avatar+18965 
+2

Here is the graph:

 

 Nov 30, 2018
 #3
avatar+805 
0

EP is right except in Interval Notation it is

(-11, 3.5), thanks EP

 

You are very welcome!

:P

 Dec 1, 2018
 #5
avatar+18965 
+1

Thanx for pointing that out ! cheeky

BUT ACTUALLY, we need interval notation with a disjunction....

   it should look like this:

(-inf, -11) U (3.5, +inf)  

 

Sorry for the confusion !   

ElectricPavlov  Dec 1, 2018
edited by ElectricPavlov  Dec 1, 2018

11 Online Users