How do you write an equation of a line through points (3,1) and (4,-4)?

1 Answer
Jim G.
Apr 27, 2018

#y=-5x+16#

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

#rArrm=(-4-1)/(4-3)=(-5)/1=-5#

#rArry=-5x+blarrcolor(blue)"is the partial equation"#

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

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

#1=-15+brArrb=1+15=16#

#rArry=-5x+16larrcolor(red)"equation of line"#

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