Question

What is an equation of the line that passes through the point (-4,-6) and is parallel to the line 2x-y=6

Answer 1

keeping in mind that parallel lines have exactly the same slope, let's check for the slope of the equation above

`2x-y=6\implies -y=-2x+6\implies y=\stackrel{\stackrel{m}{\downarrow }}{2} x-6\leftarrow \begin{array} \cline{1-1} slope-intercept~form\\ \cline{1-1} \\ y=\underset{y-intercept}{\stackrel{slope\qquad }{\stackrel{\downarrow }{m}x+\underset{\uparrow }{b}}} \\\\ \cline{1-1} \end{array}`

so we're really looking for the equation of a line whose slope is 2 and it passes through (-4 , -6)

`(\stackrel{x_1}{-4}~,~\stackrel{y_1}{-6})\hspace{10em} \stackrel{slope}{m} ~=~ 2 \\\\\\ \begin{array} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-\stackrel{y_1}{(-6)}=\stackrel{m}{ 2}(x-\stackrel{x_1}{(-4)}) \implies y +6= 2 (x +4) \\\\\\ y+6=2x+8\implies y=2x+2`