Look at the function below:
y=(2x−21)(x−241)
Then determine for which values of x the following is true:
f(x) > 0
To solve this problem, we will examine the intervals defined by the roots of the quadratic function.
Step 1: Find the roots of each factor:
For 2x−21=0, solve for x:
2x=21⇒x=41
For x−241=0, solve for x:
x=241
Step 2: Determine the test intervals around these roots, which are x<41, 41<x<241, and x>241.
Step 3: Test each interval to determine where the product is positive:
- For x<41, both factors (2x−21) and (x−241) are negative, so the product is positive.
- For 41<x<241, one factor is positive (2x−21) and the other is negative (x−241), resulting in a negative product.
- For x>241, both factors (2x−21) and (x−241) are positive, so the product is positive.
Therefore, the solution for f(x)>0 is when x>241 or x<41.
The correct choice that matches this analysis is:
x>241 or x<41.
x > 2\frac{1}{4} or x < \frac{1}{4}