How do you write the equations of a line passing through (5,-1) and (8,-3) in standard form?

1 Answer
Jun 13, 2018

#2x+3y=7#

Explanation:

#"the equation of a line in "color(blue)"standard form"# is.

#color(red)(bar(ul(|color(white)(2/2)color(black)(Ax+By=C)color(white)(2/2)|)))#

#"where A is a positive integer and B, C are integers"#

#"to start with obtain the equation in "color(blue)"slope-intercept form"#

#•color(white)(x)y=mx+b#

#"where m is the slope and b the y-intercept"#

#"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)=(5,-1)" and "(x_2,y_2)=(8,-3)#

#m=(-3-(-1))/(8-5)=(-2)/3=-2/3#

#y=-2/3x+blarrcolor(blue)"is the partial equation"#

#"to find b substitute either of the 2 given points into"#
#"the partial equation"#

#"using "(8,-3)" then"#

#-3=-16/3+brArrb=-9/3+16/3=7/3#

#y=-2/3x+7/3larrcolor(red)"in slope-intercept form"#

#"multiply all terms by 3"#

#3y=-2x+7#

#2x+3y=7larrcolor(red)"in standard form"#