Question

Write an equation for the line parallel to y = –2x – 5 that contains P(–8, 4).

Answer 1

`k:\ y = -2x -5 \ \ \ and\ \ \ l:\ y=mx+b\\\\k\ ||\ l\ \ \ \Leftrightarrow\ \ \ m=-2\ \ \ l:\ y=-2x+b\\\\ P(-8, 4)\ \in\ l\ \ \ \Leftrightarrow\ \ \ 4=-2\cdot(-8)+b\\\\\ \ \ \Leftrightarrow\ \ \ 4=16+b\ \ \ \Leftrightarrow\ \ \ b=-12\ \ \ \Rightarrow\ \ \ l:\ y=-2x-12`

Answer 2

`k:y=-2x-5\\\\l:y=mx+b\\\\k\ ||\ l\iff m=-2\\\\l:y=-2x+b;\ P(-8;\ 4)\\\\-2\cdot(-8)+b=4\\16+b=4\\b=4-16\\b=-12\\\\Answer:y=-2x-12`