SOLUTION: Inequality Graphs, how to sketch a graph for the following inequality: (x-2)(x-3)<0.

Algebra ->  Algebra  -> Inequalities -> SOLUTION: Inequality Graphs, how to sketch a graph for the following inequality: (x-2)(x-3)<0.      Log On

Ad: Algebrator™ solves your algebra problems and provides step-by-step explanations!
Ad: Algebra Solved!™: algebra software solves algebra homework problems with step-by-step help!

   


Question 57260This question is from textbook Pure Mathematics 1
: Inequality Graphs,
how to sketch a graph for the following inequality: (x-2)(x-3)<0.
This question is from textbook Pure Mathematics 1

Answer by Scriptor(36) About Me  (Show Source):
You can put this solution on YOUR website!
Hello,
I always make a table.
On the top line, I put he zeros of he funcion. In this case: 2 and 3
Then I a look at the sign of (x-2) and (x-3) while I variate x.
Let's take a look at this table:
x ->_____________2_________3_______________________

(x-2) = - - - - - - - - 0 + + + + + + + + + + + + + + +

(x-3) = - - - - - - - - - - - - - - - - -0 + + + + + + + + +

________________________________________
f(x)= + + + + + + + + 0 - - - - - - - - - 0 + + + + + + + + +

If x < 2 , then (x-2) is negative: put a '-'sign
if x = 2, then (x-2) = 0
If x > 2, then x-2 is positive: put a '+'sign
Do the same for x-3
Now think in vertical lines when looking to the table.
In the last line, you first take over the zeros. Then you put a + or a - sign. The last line is the mutiplication of the (x-2) and (x-3) line.
This means that: - and - gives a +
+ and + gives a +
+ and - gives a -
- and + gives a -
We know read from the last line that f(x) is < 0 between 2 and 3.
The answer: f(x) < 0 if x is in ]2,3[
Here's a visual plot:
+graph%28+300%2C+200%2C+-2%2C+5%2C+-1%2C+3%2C+%28x-2%29%2A%28x-3%29%29+
Greets,
Scriptor