Find the positive and negative domains of the function below:
y=(x+10)2−3
To solve this problem, we need to determine when y=(x+10)2−3 is greater than and less than zero.
Start by finding the roots of the equation:
Set y=0:
(x+10)2−3=0
Rearrange the equation to find:
(x+10)2=3
Take the square root of both sides:
x+10=±3
Solving these gives:
- x=−10+3
- x=−10−3
These roots divide the number line into three intervals:
- (−∞,−10−3)
- (−10−3,−10+3)
- (−10+3,∞)
Test each interval to determine where the function is positive or negative:
For x<−10−3: Choose x=−11
Then: y=((−11+10)2−3)=1−3=−2
So, y<0 in the interval (−∞,−10−3).
For −10−3<x<−10+3: Choose x=−10
Then: y=((−10+10)2−3)=0−3=−3
So, y<0 in the interval (−10−3,−10+3).
For x>−10+3: Choose x=0
Then: y=((0+10)2−3)=100−3=97
So, y>0 in the interval (−10+3,∞).
Therefore, the positive domain is x>−10+3 while the negative domain is x<−10+3.
Using the analysis above and applying it to the choices, the correct response is:
x<0:−10−3<x<−10+3
x>−10+3 or x>0:x<−10−3
x < 0 : -10-\sqrt{3} < x < -10-\sqrt{3}
x > -10+\sqrt{3} or x > 0 : x < -10-\sqrt{3}