What is the equation of the line passing through #(24,18)# and #(9,12)#?

2 Answers
Jun 8, 2018

#y=2/5x+42/5#

Explanation:

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

#•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)=(24,18)" and "(x_2,y_2)=(9,12)#

#m=(12-18)/(9-24)=(-6)/(-15)=2/5#

#y=2/5x+blarrcolor(blue)"is the partial equation"#

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

#"using "(9,12)" then"#

#12=18/5+brArrb=60/5-18/5=42/5#

#y=2/5x+42/5larrcolor(red)"is equation of line"#

Jun 8, 2018

#y=2/5*x+42/5#

Explanation:

We get the slope as
#m=(y_2-y_1)/(x_2-x_1)=(12-18)/(9-24)=2/5#
so we have
#y=2/5x+n#
using
#x=9,y=12#
we get
#n=42/5#