How do you write the equation in point slope form given (3,8) and (9,0)?

2 Answers
Apr 29, 2018

#y-8=-4/3(x-3)#

Explanation:

#"the equation of a line in "color(blue)"point-slope form"# is.

#•color(white)(x)y-y_1=m(x-x_1)#

#"where m is the slope and "(x_1,y_1)" a point on the line"#

#"to calculate m use the "color(blue)"gradient formula"#

#•color(white)(x)m=(y_2-y_1)/(x_2-x_1)#

#"let "(x_1,y_1)=(3,8)" and "(x_2,y_2)=(9,0)#

#rArrm=(0-8)/(9-3)=(-8)/6=-4/3#

#"using "(x_1,y_1)=(3,8)" as a point on the line then"#

#y-8=-4/3(x-3)larrcolor(red)"in point-slope form"#

Apr 29, 2018

See a solution step below..

Explanation:

Recall the equation of a line is;

#y = mx + c#

Where;

#m = "slope"#

Also recall that;

#m = (y₂ - y_1)/(x₂ - x_1)#

where;

#y₂ = 0#

#y_1 = 8#

#x₂ = 9#

#x_1 = 3#

substituting the values

#m = (0 - 8)/(9 - 3)#

#m = -8/6#

#m = -4/3#

using these points #(3, 8)# to get the slope form..

#y - y_1 = m (x - x_1)#

Therefore;

#y - 8 = -4/3 (x - 3)#

As required..