How do you write the equation of a line given (-4,6) (-1,-3)?

1 Answer
Jim G.
May 2, 2018

#y=-3x-6#

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)=(-4,6)" and "(x_2,y_2)=(-1,-3)#

#rArrm=(-3-6)/(-1-(-4))=(-9)/3=-3#

#rArry=-3x+blarrcolor(blue)"is the partial equation"#

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

#"using "(-1,-3)" then"#

#-3=3+brArrb=-3-3=-6#

#rArry=-3x-6larrcolor(red)"is equation of line"#

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