Answer:
![y=-\frac{1}{3}x+7](https://tex.z-dn.net/?f=y%3D-%5Cfrac%7B1%7D%7B3%7Dx%2B7)
Step-by-step explanation:
The slope-intercept form is:
; where <em>m </em>is the slope, and <em>b </em>is the <em>y-axis </em>interception.
So, the problem is asking for a line that it's perpendicular to
. This perpendicular relation means that the line we have to find have an inverse and opposite slope than the given line, that's expressed like this:
![m_{1}m_{2}=-1](https://tex.z-dn.net/?f=m_%7B1%7Dm_%7B2%7D%3D-1)
That expression is the condition to have perpendicular lines. So, the given line has a slope of 3, now we can find the slope of the new line:
![m_{1}m_{2}=-1\\m_{1}=\frac{-1}{m_{2}}=-\frac{1}{3}](https://tex.z-dn.net/?f=m_%7B1%7Dm_%7B2%7D%3D-1%5C%5Cm_%7B1%7D%3D%5Cfrac%7B-1%7D%7Bm_%7B2%7D%7D%3D-%5Cfrac%7B1%7D%7B3%7D)
Now we have the slope of the new perpendicular line, we use the point-slope formula to find its equation:
![y-y_{1}=m(x-x_{1})\\ y-7=-\frac{1}{3}(x-0)\\y=-\frac{1}{3}x+7](https://tex.z-dn.net/?f=y-y_%7B1%7D%3Dm%28x-x_%7B1%7D%29%5C%5C%20y-7%3D-%5Cfrac%7B1%7D%7B3%7D%28x-0%29%5C%5Cy%3D-%5Cfrac%7B1%7D%7B3%7Dx%2B7)
Therefore, the slope-intercept form of the new perpendicular line is:
![y=-\frac{1}{3}x+7](https://tex.z-dn.net/?f=y%3D-%5Cfrac%7B1%7D%7B3%7Dx%2B7)