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

Guest Nov 30, 2018

#1**+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

ElectricPavlov Nov 30, 2018

#3**0 **

EP is right except in Interval Notation it is

(-11, 3.5), thanks EP

You are very welcome!

:P

CoolStuffYT Dec 1, 2018

#5**+1 **

Thanx for pointing that out !

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