Question

Find the equation of the line with x-intercept (-4,0) and the y-intercept (0,9) algebraically

Answer 1

`\bf \stackrel{x-intercept}{(\stackrel{x_1}{-4}~,~\stackrel{y_1}{0})}\qquad \stackrel{y-intercept}{(\stackrel{x_2}{0}~,~\stackrel{y_2}{9})} ~\hfill \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{9}-\stackrel{y1}{0}}}{\underset{run} {\underset{x_2}{0}-\underset{x_1}{(-4)}}}\implies \cfrac{9}{0+4}\implies \cfrac{9}{4}`

`\bf \begin{array}ll \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}{0}=\stackrel{m}{\cfrac{9}{4}}[x-\stackrel{x_1}{(-4)}] \\\\\\ y=\cfrac{9}{4}(x+4)\implies y = \cfrac{9}{4}x+9`

Answer 2

Y=(9/4)x+9

Explanation:

You can use the slope formula to find the slope (look up on google) for m and then the y intercept is given so the is your b.