Avery drew a line on the coordinate plane that passes through the points (-1,12) and (3,-4). What equation below represents the line that Avery drew?

#(a)color(white)(.) y=1/4x+8; color(white)("dd") (b)color(white)(.) y=-8x+4; color(white)("dd") (c)color(white)(.) y=-4x + 8;# #and (d)color(white)(.) y= -4x + 4#

1 Answer
Jim G.
May 10, 2018

#y=-4x+8#

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)=(-1,12)" and "(x_2,y_2)=(3,-4)#

#rArrm=(-4-12)/(3-(-1))=(-16)/4=-4#

#rArry=-4x+blarrcolor(blue)"is the partial equation"#

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

#"using "(3,-4)" then"#

#-4=-12+brArrb=-4+12=8#

#rArry=-4x+8larrcolor(red)"is the equation of the line"#

Related questions
Impact of this question
623 views around the world
You can reuse this answer
Creative Commons License