Answer:
1)
![\text{ Slope = -3}](https://tex.z-dn.net/?f=%5Ctext%7B%20Slope%20%3D%20-3%7D)
2)
![y+4=-\frac{7}{8}(x-7)](https://tex.z-dn.net/?f=y%2B4%3D-%5Cfrac%7B7%7D%7B8%7D%28x-7%29)
3)
![y=-\frac{7}{8}x+\frac{17}{8}](https://tex.z-dn.net/?f=y%3D-%5Cfrac%7B7%7D%7B8%7Dx%2B%5Cfrac%7B17%7D%7B8%7D)
Step-by-step explanation:
We want to write the equation of the line that passes through the points (7, -4) and (-1, 3) first in point-slope form and then in slope-intercept form.
1)
First and foremost, we will need to find the slope of the line. So, we can use the slope-formula:
![m=\frac{y_2-y_1}{x_2-x_1}](https://tex.z-dn.net/?f=m%3D%5Cfrac%7By_2-y_1%7D%7Bx_2-x_1%7D)
Let (7, -4) be (x₁, y₁) and let (-1, 3) be (x₂, y₂). Substitute them into our slope formula. This yields:
![m=\frac{3-(-4)}{-1-7}](https://tex.z-dn.net/?f=m%3D%5Cfrac%7B3-%28-4%29%7D%7B-1-7%7D)
Subtract. So, our slope is:
![m=\frac{7}{-8}=-7/8](https://tex.z-dn.net/?f=m%3D%5Cfrac%7B7%7D%7B-8%7D%3D-7%2F8)
2)
Now, let's use the point-slope form:
![y-y_1=m(x-x_1)](https://tex.z-dn.net/?f=y-y_1%3Dm%28x-x_1%29)
We will substitute -7/8 for our slope m. We will also use the point (7, -4) and this will be our (x₁, y₁). So, substituting these values yield:
![y-(-4)=-\frac{7}{8}(x-7)](https://tex.z-dn.net/?f=y-%28-4%29%3D-%5Cfrac%7B7%7D%7B8%7D%28x-7%29)
Simplify. So, our point-slope equation is:
![y+4=-\frac{7}{8}(x-7)](https://tex.z-dn.net/?f=y%2B4%3D-%5Cfrac%7B7%7D%7B8%7D%28x-7%29)
3)
Finally, we want to convert this into slope-intercept form. So, let's solve for our y.
On the right, distribute:
![y+4=-\frac{7}{8}x+\frac{49}{8}](https://tex.z-dn.net/?f=y%2B4%3D-%5Cfrac%7B7%7D%7B8%7Dx%2B%5Cfrac%7B49%7D%7B8%7D)
Subtract 4 from both sides. Note that we can write 4 using a common denominator of 8, so 4 is 32/8. This yields:
![y=-\frac{7}{8}x+\frac{49}{8}-\frac{32}{8}](https://tex.z-dn.net/?f=y%3D-%5Cfrac%7B7%7D%7B8%7Dx%2B%5Cfrac%7B49%7D%7B8%7D-%5Cfrac%7B32%7D%7B8%7D)
Subtract. So, our slope-intercept equation is:
![y=-\frac{7}{8}x+\frac{17}{8}](https://tex.z-dn.net/?f=y%3D-%5Cfrac%7B7%7D%7B8%7Dx%2B%5Cfrac%7B17%7D%7B8%7D)
And we're done!