How do you graph the line # 2x - 5y=10#?

1 Answer
Apr 10, 2016

Transpose (manipulate) the equation as follows:

Add #color(blue)(5y)# to both sides

#color(brown)(2x-5ycolor(blue)(+5y)=10color(blue)(+5y))" "->" "2x+0=10+5y#

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtract #color(blue)(10)# from both sides

#color(brown)(2xcolor(blue)(-10)=10color(blue)(-10)+5y)" "->" "2x-10=0+5y#

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Divide both sides by #color(blue)(5)#

#color(brown)( (2x)/(color(blue)(5)) -10/(color(blue)(5)) = 5/(color(blue)(5)) xx x#

But #5/5=1#

#color(blue)(y=2/5 x-2)" " #This is standard form of the equation
#color(red)("=================================")#

The line crosses the y-axis ( #y_("intercept"# ) when #x=0#

so #y_("intercept")= 2/5 (0)-2 = -2#

So one point is:#" "(x,y)->(0,-2)#

#color(red)("Mark that point on the graph")#
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The line crosses the x-axis ( #x_("intercept")# ) at #y=0#

#0=2/5 x-2#

#=> 2 xx5/2=x = 5#

So the other point is:#" "(x,y)->(5,0)#
#color(red)("Mark that point on the graph")#
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(blue)("Draw a line through both these points and that is your graph.")#

Tony B