How do you find the x and y intercept of #3x − y = 5 #?

1 Answer
Jul 7, 2016

Answer:

#x_("intercept")=5/3#

#y_("intercept")=-5#

Explanation:

#color(blue)("Determine "y_("intercept"))#

The y-axis crosses the x-axis at #x=0# so to find the y-intercept substitute #x=0# into the equation

#color(brown)(3x-y=5)color(blue)(" "->" "3(0)-y=5#

But #3xx0=0# giving

#-y=5#

Multiply both sides by #(-1)#

#(-y)xx(-1)=5xx(-1)#

#y=-5#
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

#color(blue)("Determine "x_("intercept"))#

The x-axis crosses the y-axis at #y=0# so to find the x-intercept substitute #y=0# into the equation

#color(brown)(3x-y=5)color(blue)(" "->" "3x-0=5#

#color(brown)(3x=5)#

Divide both sides by #color(blue)(3)#

#color(brown)(3/(color(blue)(3)) xx x=5/(color(blue)(3))#

But #3/3=1#

#x=5/3#

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(brown)(3x-y=5)" "->" "color(blue)(y=3x-5)#
Tony B