Answer:
![n = 304](https://img.qammunity.org/2021/formulas/mathematics/high-school/9c5p2cex6913omhu5zhmn5hia471yo8jrn.png)
Explanation:
Given
![y = -15x - 6](https://img.qammunity.org/2021/formulas/mathematics/high-school/agn0d5wk2kd6fd5pfuyjm3cwv188tlxn23.png)
![Points: (n,-12) \& (4,8)](https://img.qammunity.org/2021/formulas/mathematics/high-school/exob4qnhcps37khozsu65b8uljrmo3f5h2.png)
Required
Determine the value of n
First, we need to determine the slope of the given equation.
An equation is of the form;
![y = m_1x + b](https://img.qammunity.org/2021/formulas/mathematics/middle-school/l5szvrjtf7ge6n1o3fot9zs2svf28jpwzx.png)
Where m = slope.
By comparison.
![m_1 = -15](https://img.qammunity.org/2021/formulas/mathematics/high-school/8be0svyt0bkrxh0cg4qw0ek176x6950lqa.png)
Since the given point and the given equation are perpendicular, then:
![m = -(1)/(m_1)](https://img.qammunity.org/2021/formulas/mathematics/high-school/7dbk26b1dx0nrs0amhzzgh2ccn8adktb1f.png)
![m = -(1)/(-15)](https://img.qammunity.org/2021/formulas/mathematics/high-school/ai67gizm34yc7omlsiu3uz6k28t1lww2yx.png)
![m = (1)/(15)](https://img.qammunity.org/2021/formulas/mathematics/high-school/ib0obg11fp7xcdmle5rvkwwcdddbkcfdsd.png)
The slope of the point is calculated as thus:
![m = (y_2 - y_1)/(x_2 - x_1)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/gjvq8ugonz7wbfcjxpwzkf808xsbjwfyvh.png)
Where
![(x_1,y_1) = (n,-12)](https://img.qammunity.org/2021/formulas/mathematics/high-school/5m2571y89ame8qtd4x4zbdo9dizdnwiilo.png)
![(x_2,y_2) = (4,8)](https://img.qammunity.org/2021/formulas/mathematics/high-school/ejfhc20k6q7nikqxl7xwhqeltgpkyosbiy.png)
![m = (1)/(15)](https://img.qammunity.org/2021/formulas/mathematics/high-school/ib0obg11fp7xcdmle5rvkwwcdddbkcfdsd.png)
So, we have:
![(1)/(15) = (8 - (-12))/(4 - n)](https://img.qammunity.org/2021/formulas/mathematics/high-school/of2uym13zo66umaki8c452a7b3glvqo242.png)
![(1)/(15) = (8 +12)/(4 - n)](https://img.qammunity.org/2021/formulas/mathematics/high-school/pfwh8x6ej56cvkvf97ptxars3ljy4w9t6p.png)
![(1)/(15) = (20)/(4 - n)](https://img.qammunity.org/2021/formulas/mathematics/high-school/i0wymegc78va3yx96txwutnutxw56z3ev0.png)
Cross Multiply
![4 - n = 20 * 15](https://img.qammunity.org/2021/formulas/mathematics/high-school/x6o49c0d4qjo72pd1fwyaovfiw4ksty7dt.png)
![4 - n = 300](https://img.qammunity.org/2021/formulas/mathematics/high-school/a20tzt7rt7byk57kz43la979e93vm9kn14.png)
Solve for n
![n = 4 + 300](https://img.qammunity.org/2021/formulas/mathematics/high-school/vgdlg1kr5wsbmfpf7334uxkd01n46j47i3.png)
![n = 304](https://img.qammunity.org/2021/formulas/mathematics/high-school/9c5p2cex6913omhu5zhmn5hia471yo8jrn.png)