Question

Write an equation in slope-intercept form for the following line: (-14.1) and (13,-2)

Answer 1

Answer:

$y=-\frac{1}{9}x-\frac{5}{9}$

Step-by-step explanation:

$(-14,1)(13,-2)$

Use the slope-intercept formula:

$y=mx+b$

m is the slope and b is the y-intercept. Use the slope formula first:

$\frac{y_{2}-y_{1}}{x_{2}-x_{1}} =\frac{rise}{run}$

Rise over run is the change in the y-axis over the change in the x-axis. Plug in the coordinates:

$(-14(x_{1}),1(y_{1}))\\(13(x_{2}),-2(y_{2}))$

$\frac{-2-1}{13-(-14)}$

Simplify parentheses (two negatives makes a positive):

$\frac{-2-1}{13+14}$

Simplify:

$\frac{-3}{27} =-\frac{3}{27}=-\frac{1}{9}$

The slope is $-\frac{1}{9}$. Insert into the equation:

$y=-\frac{1}{9}x +b$

Now, to find the y-intercept, take one of the points and substitute for the x and y values of the equation:

$(13,-2)\\-2=-\frac{1}{9} (13)+b$

Solve for b, the y-intercept. Simplify parentheses:

$-\frac{1}{9}*\frac{13}{1}=-\frac{13}{9}$

$-2=-\frac{13}{9} +b$

Add $-\frac{13}{9}$  to both sides:

$-2+\frac{13}{9}=-\frac{13}{9} +\frac{13}{9} +b\\\\-2+\frac{13}{9} =b$

Simplify:

$-\frac{2}{1} +\frac{13}{9}\\\\-\frac{18}{9}+\frac{13}{9}\\ \\b=-\frac{5}{9}$

The y-intercept is $-\frac{5}{9}$ . Insert this into the equation:

$y=-\frac{1}{9} x-\frac{5}{9}$

Finito.