Answer:
The x-intercept of L is 0
Step-by-step explanation:
1)  If (a,b) and (c,d) belongs to theline L, then the equation of the line using two-points formula  will be:
[tex]y-b=(\frac{b-d}{a-c} ).(x-a)[/tex]
if we want to find the x-intercept of L we should set y=0.
[tex]0-b=(\frac{b-d}{a-c} ).(x-a)[/tex]
getting x from that equation we will have :
[tex]x=-b.\frac{a-c}{b-d}+a[/tex]
using distributive propertie and common denominator will be obtain
x= [tex]x= \frac{bc-ad}{b-d}[/tex]
as we know that ad=bc the numerator will be equal to zero. Then x=0.
2) Using the same equation of line but using the points(m,n) and (-m, -n) we will set it as:
[tex]y-n=\frac{-2n}{-2m}.(x-m)[/tex]
if we want to find the x-intercept of L we should set y=0.
[tex]0-n=\frac{-2n}{-2m}.(x-m)[/tex]
getting x from that equation we will have :
[tex]-n=\frac{n}{m}(x-m)[/tex]
[tex]x= -n.\frac{m}{n} + m[/tex]
them
x = 0
