Given:
The function is:
![f(x)=-2x+1](https://tex.z-dn.net/?f=f%28x%29%3D-2x%2B1)
To find:
a. Slope and Y-intercept.
b. Is the function increasing, decreasing, or constant, justify your answer.
c. Graph the function, label x, and y-intercepts.
Solution:
a. We have,
...(i)
The slope intercept form of a line is:
...(ii)
Where, m is the slope and b is the y-intercept.
On comparing (i) and (ii), we get
![m=-2,b=1](https://tex.z-dn.net/?f=m%3D-2%2Cb%3D1)
Therefore, the slope of the line is -2 and the y-intercept is 1.
b. If the slope of a linear function is negative, then the function is decreasing.
If the slope of a linear function is positive, then the function is increasing.
If the slope of a linear function is 0, then the function is constant.
The slope of the linear function is negative.
Therefore, the function is decreasing.
c. We have,
![f(x)=-2x+1](https://tex.z-dn.net/?f=f%28x%29%3D-2x%2B1)
At
, we get
![f(0)=-2(0)+1](https://tex.z-dn.net/?f=f%280%29%3D-2%280%29%2B1)
![f(0)=1](https://tex.z-dn.net/?f=f%280%29%3D1)
So, the y-intercept is at (0,1).
At
, we get
![0=-2x+1](https://tex.z-dn.net/?f=0%3D-2x%2B1)
![2x=1](https://tex.z-dn.net/?f=2x%3D1)
![x=\dfrac{1}{2}](https://tex.z-dn.net/?f=x%3D%5Cdfrac%7B1%7D%7B2%7D)
![x=0.5](https://tex.z-dn.net/?f=x%3D0.5)
So, the x-intercept is at
.
Plot the points
and connect them by a straight line as shown below: