Question

Find the equation of a line that passes through the point (0,-1) and has a gradient of -3. Leave your answer in the form y = m x + c

Answer 1

the slope goes by several names

• average rate of change

• rate of change

• deltaY over deltaX

• Δy over Δx

• rise over run

• gradient

• constant of proportionality

however, is the same cat wearing different costumes.

`(\stackrel{x_1}{0}~,~\stackrel{y_1}{-1})\hspace{10em} \stackrel{slope}{m} ~=~ - 3 \\\\\\ \begin{array}c \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}{(-1)}=\stackrel{m}{- 3}(x-\stackrel{x_1}{0}) \implies y +1= -3 (x -0) \\\\\\ y+1=-3x\implies {\Large \begin{array}{llll} y=-3x-1 \end{array}}`