what is a dual intercept method and how is it applied?

4 answers

The x-intercept of a line is the point at which the line crosses the x axis.
( i.e. where the y value equals 0 )

x-intercept = ( x, 0 )

The y-intercept of a line is the point at which the line crosses the y axis. ( i.e. where the x value equals 0 )

y-intercept = ( 0, y )


When the equation of a line is given in STANDARD FORM:

y = mx + b

so the easiest way to graph it is probably the DUAL-INTERCEPT METHOD.

Instead of having to solve for y in terms of x in order to find the slope and y-intercept, I think it is much easier to just find the x and y intercepts.

EXAMPLE :

2x + y = -2

SOLUTION:

If x = 0, then y = -2 That is the y - intercept

If y = 0, then 2x = -2,Divide both sides with 2 so x = -1 is the x - intercept

Graph points:
x = 0 , y = -2

and

x = -1 , y = 0

in a coordinate system and connect the dots.
Just FYI, if you draw a line through the two intercepts (0,k) and (h,0), then the equation is

(y-k)/(x-h) = -k/h

kx + hy = 2hk
Xy=2
the x value of the y-intercept=0