Writing an equation using the point slope formula.

[ThatOneGuy]

The two points given are P(17,-2) and Q(23,-6). The instructions say to write the equation of the line using the point-slope formula. There is no specific part I'm confused with, but seeing an example will help.

 

[Loren]

P(1,5) and Q(5,6)

Pt-slope form is y=mx+b where m is the slope of the line and b is the y-intercept.

\(\displaystyle m=\frac{y_2-y_1}{x_2-x_1}=\frac{6-5}{5-1}=\frac{1}{4}\)

Equation of a line through two points is given by \(\displaystyle y-y_1=m(x-x_1)\)

\(\displaystyle y-5=\frac{1}{4}(x-1)\)
\(\displaystyle 4y-20=x-1\)
\(\displaystyle 4y=x+19\)
\(\displaystyle y=\frac{1}{4}x+\frac{19}{4}\)

 

[Denis]

Too tired to do a google search? :shock:

http://www.purplemath.com/modules/strtlneq2.htm