two intercept form

Question

show that an equation of a line through the points (a,0) and (0,b), with a and b nonzero, can be written in the form 

x/a+y/b=1

This form is called the two-intercept form of the equation of a line. 

Answer 1

You already have the y-intercept at (0,b), so

 

y = mx + b

 

m = (b - 0)/(0 - a) = -b/a

 

y = (-b/a)x + b

 

y/b = -x/a + 1

 

x/a + y/b = 1