How do you find the x and y intercepts for #2x - y = 8#?

2 Answers
Apr 9, 2017

Answer:

x-intercept: #4#
y-intercept: #-8#

Explanation:

The x-intercept is the value of #x# where the equation crosses the X-axis; that is it is the value of #x# when #y=0#.
Substituting #0# for #y# in #2x-y=8#
#color(white)("XXX")2x-0=8color(white)("xxx")rarrcolor(white)("xxx")x=4#
[Some instructors prefer to have the intercept written as as a coordinate pair; in this case, the coordinates for the x-intercept would be #(4,0)#].

Similary, the y-intercept is the value of #y# when #x=0#.
Substituting #0# for #x# in #2x-y=8#
#color(white)("XXX")2 * 0 -y =8 color(white)("xxx")rarrcolor(white)("xxx")y=-8#
[...or, given as a coordinate pair: #(0,-8)#].

Apr 9, 2017

Answer:

See the entire solution process below:

Explanation:

To find the #y# intercept, set #x# equal to #0# and solve for #y#:

#2x - y = 8# becomes:

#(2 * 0) - y = 8#

#0 - y = 8#

#-y = 8#

#color(red)(-1) * -y = color(red)(-1) * 8#

#y = -8#

The y-intercept is #-8# or #(0, -8)#

To find the #x# intercept, set #y# equal to #0# and solve for #x#:

#2x - y = 8# becomes:

#2x - 0 = 8#

#2x = 8#

#(2x)/color(red)(2) = 8/color(red)(2)#

#(color(red)(cancel(color(black)(2)))x)/cancel(color(red)(2)) = 4#

#x = 4#

The x-intercept is #4# or #(4, 0)#